I wouldn't be so sure. If memory serves me correctly, back in 1991 when I did my airline summer internship, the average $/pax spent on coach meals ranged from just under $4 to $8.50. With inflation, I wouldn't surprised if the $10 figure was accurate (even taking into account recent cutbacks). In any case, this information is readily available in airline industry publications (if anyone cares to do a little research).