Defending WDC gets #1, current teammate gets #2. The remaining teams are given numbers in accordance with their Constructor's Championship standings from the previous season. What number each driver gets is up to the teams, whether by the Driver's Championship standings or in the order of registration with the FIA.
It would seem courteous for Ferrari to give Massa #3 and Raikko #4, but it needn't be that way. If Ferrari thinks Raikko is the more important driver, or the registration paperwork for Raikko's happen to be on top of Massa's, then Raikko gets #3.
On the topic of car numbers, I wish the numbers are painted more visibly on the cars. You can't see them these days.
I've travelled on planes a lot, and no, the food isn't usually that bad. The only truly bad thing I've tasted was fish. I've seen some weird chicken stuff too. But usually they're edible and reasonably tasty.
Most of the lunch and dinner main course dishes are literally frozen stuff they've warmed in a heater. Breakfasts are usually pretty good (usually just milk and cereal, with some yoghurt or fruit juice). Lunch and dinner entree and desserts are pretty good too.
Honestly, the pictures in the article I linked look really bad, even for airline food. I'd think thrice before touching the stuff, let alone eating them.