CPH
In the old T2 transit area there is a rather nice Hereford restaurant that does a nice steak.
OSL
Nothing. Absolutely nothing, and what they have costs an arm and a leg. Bring a sandwich.
BRU
The 'Pilots Club' restaurant on the 3rd level in departures is nice, but not cheap.
SDA
If you drop by the DHL office, they might offer you a cold bottle of water just for the pleasure of seeing a friendly face. The Indian chef might have a bowl of chiken chikka if you're lucky (or not, as the case often is).
KBL
The chow place next to the PX does a very nice breakfast at rock bottom price. Eat in the company of US Marines and an assortment of other soldiers, and buy a t-shirt on the way out.
HRE
Nope. Nada, zip, zilch, nothing.
PTY
Second floor in departures, up the escalators and to the right. Nice little cafeteria type thing that does the most wonderful freshly pressed juices. Pretty good burgers too.
JNB
Fast food joint in departures that does a very nice chicken burger.
FRA
In departures, just before entrance to T1B there is a restaurant with pretty good ham/cheese sandwiches at around EUR 2.50. Beats bringing your own, but that's about it.
MIA
Restaurant up on the 5th floor or something does great steaks.
BAH
Fast food joint in departures (it's a chain, forgot the name) does a very nice and cheap chicken salad. Alternatively, if you're in F or J with GF the lounge in the transit area is very nice, but all non-smoking.
LOS
You must be joking!
IAD
Well, there's a Burger King .....
LYS
Very nice restaurant at the entrance to the airport hotel. Sports a very nice selection of wines too.