If you want to eat at the airport with the dual purpose of watching aeroplane activity at the same time then the low-brow grub at Leicester might fit the bill.............
However if you want merely to take him to lunch by aeroplane and aren't fussed about watching aeroplanes then the Crab & Lobster at Bembridge wins hands down.
Two caveats:
1) don't walk, get a taxi (ask tower to ring for one the moment you land)
2) It'll be packed, ring the day before and book a table .(the day before might even be too late)
Enjoy
Cusco