Length Very good
The word “Airline Credit” contains only two words. Can be used for Airline Rewards, Credit Cards.
Airlinecredit.com is a dot-com domain. Dot com domains are the most prestigious top-level-domain in the world, famously used by websites like twitter.com. Once secured, a dot-com all but guarantees no-one else can outrank you for your own name in the long run.