Room temperature fruit would be ok to feed her. Finger foods like cheerios, or banana would be a good idea also. Graham crackers can be gummed pretty good at that age. At this age they like to experiment with finger foods so I would think those would be just fine, and they get a kick out of feeding themselves.
Hope that helps some
:7
PS- the stewardess might be able to heat some baby food for you too, never hurts to ask