The scenario
You booked directly with American. Your second leg gets canceled - or delays make it impossible. The airline can't get you out until tomorrow, but TripHero finds a Delta flight that gets you home tonight. You take the Delta flight. Smart move.
Here's what most travelers don't realize
That unflown American leg is still your money. When an airline cancels or significantly delays your flight and you don't fly it, you're generally entitled to compensation for the unused portion - typically a refund to your original payment method (U.S. DOT rules for cancellations and significant changes) or, at minimum, a travel credit for future flights. Booking your rescue flight on Delta doesn't erase that.
What to do when you switch airlines
Don't cancel your original ticket yourself before the airline cancels or officially delays the flight - let the disruption be on their side of the ledger. Your rights are stronger when they broke the schedule, not you.
Ask for a refund of the unflown segment, not just a credit. For a cancellation or significant schedule change, a cash refund of the unused portion is generally your right - a travel credit is the fallback, not the ceiling.
Get it in writing before you walk away. A quick request at the desk, in the app, or on the phone: "Please document that flight AA 5318 was canceled and I'm requesting a refund of the unflown segment." Screenshot everything.
Watch the expiration date on credits. If you do end up with a travel credit instead of a refund, most expire 12 months from the original booking date (policies vary by airline). TripHero can remind you before it expires.
The bottom line
Choosing the fastest way home - even on a different airline - is almost always the right call. Just remember you're walking away with two things: a seat on the flight that saves your night, and money owed to you by the airline that couldn't. TripHero flags this on cross-airline rebooking options so you are less likely to leave value on the table.
This is general guidance, not legal or financial advice. Refund and credit policies vary by airline, fare type, and cause of disruption; international itineraries may carry additional rights (e.g. EU261/UK261). Always confirm with your airline.