What it typically does not cover
- Taxes and government charges, which on some routes are a large share of the total.
- Baggage fees, seat selection and other extras.
- Partner-operated flights sold under the airline's number but flown by another carrier.
- Hotels and cars booked through the airline's own travel site.
So a given amount of credit does not buy a ticket of that price. If you are aiming to cover a specific journey, expect a meaningful bill on top.
Codeshare is the one people miss
A flight sold by one airline and operated by another may not accept that airline's credit. The booking looks like it belongs to them right up until payment.
If the trip is already chosen, check which airline actually operates it.
Named traveller
Airline credit is often usable for a booking in anyone's name, but the rules differ and some products are restricted to the purchaser. If the gift is for someone else to fly, say so up front rather than discovering a restriction at the checkout.
Expiry
Travel credit commonly carries an expiry, and it is frequently shorter than retail gift cards. Check the date early and plan backwards from it.
Who it suits
Someone with a trip planned on that airline. Poor as a speculative gift — unused travel credit is the most reliably wasted kind there is.
Asking for one
Country, amount, and the route if it is known. The travel guide covers what airline credit generally excludes.