Ecco in the ATL international terminal. Pricey but worth it. Other than that I don't frequent airline terminals that much, but here are a few other suggestions for us corporate and 135 people that use FBOs:
Anytime in OPF is worth a quick courtesy car trip to the Latin American Grill, some of the best Cuban food you'll ever have stateside
The sketchy taco truck outside of Signature East in VNY is solid, but even better grab a car and head down the street to Salsa and Beer. There can often be a long line but it will be memorable. They have another location closer to BUR if you land there instead.
In LAS Aloha kitchen is a short ride from both Signature and Atlantic and has some great Hawaiian food, but if you have a bit more time on your hands head all the way into old downtown at The California hotel and eat at Aloha Specialties on the mezzanine level. Life changing Hawaiian food right there. Or anything from Eataly at Park MGM but parking can be a pain depending on what time you go. If you go to HND instead a quick drive to Settebello will yield you some great Neapolitan pizza.
FBO at XNA has hot dogs and ice cream. MillionAir in GPT has incredibly cheap hot sandwiches they make that are actually good.