Why Flight Data Matters
When you file a compensation claim, the airline controls the narrative — at least initially. They have access to ATC logs, maintenance records, and crew schedules. You have your memory of standing in the terminal watching the departure board flip from "On Time" to "Delayed" to "Cancelled."
Flight tracking data levels that playing field. Third-party sources capture ATC radar positions, actual gate pushback times, wheels-off and wheels-on timestamps, and gate arrival times — independently of what the airline tells you. Under EU261, Canadian APPR, and in US complaint processes, documented flight data is strong evidence. It can show:
- The exact delay duration at your destination (which determines which compensation tier applies)
- Whether the delay was caused by a late inbound aircraft — and whether that aircraft's earlier delay was weather-related or operational
- Whether other flights at the same airport were unaffected (undermining an "extraordinary circumstances" defense)
- Whether the airline's stated reason for delay matches what actually happened operationally
This phrase tells you nothing. It does not distinguish between a weather diversion (outside airline's control) and a crew scheduling failure (within airline's control). When you see this language, it is a signal to dig deeper into the actual flight data.
Primary Data Sources
The most widely used flight tracking platform for historical data. Shows actual gate departure, wheels-off, wheels-on, and gate arrival for any specific flight. Historical data going back years is available through their paid Misery Map and Flight History features. The free search gives you the last few months.
Strong on real-time ADS-B radar data and historical playback. Particularly useful for international flights and for reconstructing the full route an aircraft flew on a given day. The "Aircraft" view lets you see every flight an individual plane operated — invaluable for tracing a late-arriving inbound that caused your delay. Historical data requires a Silver or Gold subscription.
The Bureau of Transportation Statistics is the official US government source for domestic airline performance data. It covers all large US carriers on domestic routes and includes official delay cause codes (carrier, weather, NAS, security, late aircraft). Data is reported by airlines to the BTS under federal reporting requirements — making it harder to dispute than third-party sources. Updated monthly, typically with a 30-45 day lag.
Operated by Cirium, a major aviation data provider. Offers historical on-time performance data for specific routes and flights. The free tier is limited, but the "Flight Status" lookup covers recent months and is useful for confirming scheduled vs. actual times quickly. Airlines and travel agencies use Cirium data commercially, which gives it credibility in disputes.
Understanding What You're Looking For
When you pull up your flight on any of these platforms, you will see several timestamps. Here is what each means for your claim:
| Data Point | What It Shows | Why It Matters |
|---|---|---|
| Scheduled departure | The time in your original booking | The baseline for calculating delay |
| Actual gate departure | When doors closed and pushback began | Confirms the aircraft was not ready on time |
| Wheels off (takeoff) | When the plane left the ground | Confirms ATC sequencing issues vs. gate issues |
| Wheels on (landing) | When the plane touched down at destination | Important for APPR/EU claims where destination arrival time is the metric |
| Actual gate arrival | When doors opened at the destination gate | The definitive delay measurement under APPR and EU261 |
| BTS delay cause code | Carrier / Weather / NAS / Security / Late Aircraft | Official US government classification; "Carrier" = within airline's control |
Tracing a Late Inbound Aircraft
This is the single most powerful technique for turning an airline's vague excuse into a concrete claim. Here is how to do it:
- Find your aircraft's tail number on FlightAware or FlightRadar24 by searching for your specific flight.
- Click the aircraft/tail number to see every flight it operated that day.
- Look at the previous flight on that tail. Was it also delayed? Where did that delay originate?
- Trace back until you find the root cause. If the root cause was a carrier issue (staffing, maintenance) rather than weather, every downstream delay in that aircraft's day may be compensable.
- Check other aircraft on the same route at the same time. Were they operating on schedule? If yes, this undercuts any airport-wide or weather excuse.
Your 6pm flight from Toronto to Vancouver is cancelled. The airline cites "weather." You check FlightAware: the same tail number had a maintenance delay in Calgary at 8am, pushing every subsequent flight on that aircraft 4+ hours behind. Weather did not cause the morning maintenance issue. This is a within-control cascade — and a compensable APPR claim.
How Airlines Use Vague Language to Deny Claims
Airlines have a strong financial incentive to avoid paying compensation, and vague denial language is the first line of defense. Common phrases and what they really may mean:
| Airline Excuse | What to Investigate | Potential Real Cause |
|---|---|---|
| "Operational reasons" | Check aircraft history, crew assignments | Crew scheduling failure, aircraft swap |
| "Late arriving aircraft" | Trace the tail number back through the day | Carrier-caused delay upstream — still compensable |
| "Weather conditions" | Check weather data + other flights on same route | May have been airport-specific and resolved; other flights not delayed |
| "Safety concerns" | Request specifics; was an MEL (maintenance log) item involved? | Known maintenance issue the airline failed to address proactively |
| "Air traffic control" | Check ATC advisories (FAA ATIS archives, NOTAM database) | ATC delay was minor; the bulk of delay was carrier-caused |
Documentation Strategy: What to Capture
Whether your delay happened yesterday or several months ago, having the right documentation dramatically strengthens your claim.
At the Airport (Real-Time)
Screenshot the departure board
Capture the flight number, status, original time, and current time. The timestamp on your phone's photo is evidence of when the delay was announced.
Screenshot airline app notifications
Every delay notification the airline sends is an admission of the schedule change. Save them — do not delete airline SMS or app alerts.
Ask for the reason in writing
Go to the gate agent and ask: "What is the reason for this delay, and can you give me that in writing or in an email?" The gate agent may not be able to provide a formal letter, but their verbal statement is worth noting (with the time and the agent's badge name if possible).
Note your actual arrival time
When you land, check the time immediately. For EU261 and APPR claims, what matters is when the aircraft doors open at the destination gate — not when wheels touched down. Take a screenshot with the time visible.
Keep all receipts
Food, transport, hotel — keep every receipt. Some jurisdictions allow out-of-pocket expense claims in addition to fixed compensation. At minimum, receipts document the human cost of the disruption.
After the Fact (Researching a Past Delay)
- Flight number + date — you need both to search any tracking platform
- Aircraft tail number — visible on FlightAware; enables inbound trace
- BTS lookup — search transtats.bts.gov for "On-Time Performance" data by carrier, origin, destination, and month
- Weather archive — Weather Underground (wunderground.com) has historical airport weather by hour; useful to counter or confirm weather claims
- NOTAM archive — the FAA publishes Notices to Air Missions; if the airline cites an ATC restriction, check whether one was actually in effect
FOIA Requests for DOT Data
For US domestic flights, if you need data that goes beyond what BTS publishes publicly — for example, specific ATC communications, accident investigation records, or detailed carrier reports — you can submit a Freedom of Information Act (FOIA) request to the DOT or the FAA.
When FOIA Makes Sense
- Your claim involves a serious incident (not just a delay) and you want the underlying investigation data
- The airline disputes documented data and you need an official government record
- You are pursuing small claims court action and need credible documentary evidence
How to Submit a DOT FOIA Request
- Go to transportation.gov/foia
- Use the online FOIA request system (FOIAonline)
- Be specific: include the flight number, date, origin, destination, and exactly what records you are requesting
- The DOT has 20 business days to respond to a standard request; complex requests can take longer
For typical delay compensation claims, BTS data and third-party trackers are usually sufficient. FOIA is most useful when an airline is actively disputing documented facts or when the claim involves a pattern of behavior (e.g., you discover the same tail number regularly has maintenance delays). Reserve it for contested, higher-value claims.
Putting It All Together: Your Evidence Package
When you submit a compensation claim, whether to the airline, the DOT, the CTA, or a court, your evidence package should include:
| Document | Source | What It Proves |
|---|---|---|
| Booking confirmation | Your email | Scheduled departure and arrival times |
| Boarding pass | Your email / phone | You were on the flight; your seat class |
| FlightAware / FR24 screenshot | Third-party tracker | Actual departure and arrival timestamps |
| BTS on-time record | transtats.bts.gov | Official US government delay duration and cause code |
| Airline notification screenshots | SMS / app / email | Airline's own admission of delay, and timing of notice |
| Departure board photo | Your phone | Real-time delay; timestamp supports your account |
| Inbound aircraft history | FlightAware tail number trace | Establishes cascade delay originated with carrier |