Apart from the standard food on most airplanes, you can usually order special meals as well. Most airlines will be able to supply some or all of the following.
Health-related
- Bland meals for people with gastric problems such as ulcers, hiatus hernia, gastric reflux
- Diabetic meals for Type I and II diabetics, or even individuals suffering from hypoglycaemia
- Gluten-free meals for patients with gluten and wheat allergies, or coeliac disease
- High-fibre meals for anyone who requires an increased dietary fibre intake
- Low-calorie meals for people who need to restrict their energy intake or those who are slimming
- Low-fat meals for slimmers or patients suffering from raised blood fat levels
- Low-protein meals for patients with kidney problems
- Low-sodium meals for individuals with hypertension or kidney problems, and anyone on a low-sodium diet
- Lactose-free meals for patients with lactose or milk allergy
- Purine-reduced meals for persons suffering from gout
Preference (eg religion) related
- Asian vegetarian or vegan meals for Hindus and other individuals who do not eat meat, fish or flesh of any kind, or milk, dairy products and eggs
- Lacto-ovo-vegetarian meals which exclude meat and fish, but still make use of eggs, milk and dairy products
- Fruit meals for those individuals who prefer to only eat fruit
- Kosher meals, which are prepared according to Jewish religious restrictions (and see comments below concerning Glatt Kosher)
- Halal meals for Muslim passengers
- Fish meals for passengers who eat only fish and no meat
Age related
Who makes them
Most of these meals are made by the airline, and are therefore likely to be just as good or as bad as the regular airline food. Kosher food is almost always made by an external supplier, as the rules are so strict (the exception is on El Al, the Israeli national airline, where all food is Kosher). This may be the case with Halal food as well.
Of course, the airlines don't check that you're Jewish and religious when you order a Kosher meal. So if you know the airline you're flying on has bad food, try ordering a Kosher meal! The ones I've had out of London are pretty good, the ones out of the USA are variable.
Ordering them
Most airlines require 48 hours notice for special meals, although they can probably deal with things like vegetarian at check in. If you're flying first class, you should receive an appropriate special meal as well. Some airlines apparently won't give you an upgrade at check in if you've got a special meal.
Footnote
Don't try ordering a Kosher meal on Iranian or Syrian airlines!
SharQ asks what would you do instead? Order vegetarian? Well, firstly, most Jews won't be admitted to the likes of Syria, Iran, Saudi Arabia etc and most people won't be admitted if you have an Israel stamp in your passport. This is one of the reasons the UK passport office will allow for a person to have two passports! I suppose vegetarian or a fruit plate would be the best option.
DejaMorgana says On airplane food, don't forget you can also order glatt kosher. Maybe not on all airlines, but on many of them. Also, it might be worth noting that there are almost always a couple of extra kosher meals and vegetarian meals on the plane to serve people who have forgotten to order specially. Several times i've had an airline screw up my rabbit food order, but there has always been an extra one on hand. Oh, and since most Iranian and Syrian airlines will have halal food automatically, the kosher traveller is probably covered in all meaningful aspects of kashrut. Of course, i haven't kept kosher since 1984, so i may be overlooking something.
Glatt Kosher is "special Kosher" which some religious Jews keep to. El Al can certainly supply this, and some others may be able to. It's certainly the case that there are often extra vegetarian meals, hence you can often order one at check in or perhaps even on board (but they'll go round for those who have pre-ordered first). Kosher is less likely, I've been caught out once or twice when forgetting to pre-order them and they haven't had any.
The Kosher vs Halal debate is a long one. My opinion is this. For a religious Jew, starving to death, Halal is better than nothing, no doubt about that (and if Halal isn't available, if it's a matter of life and death, you can eat anything). For example, it's never been near pork or other pig products. On the other hand, Halal has no prohibition about mixing milk and meat - and according to the laws of Kashrut, having a piece of Kosher meat with a milk-based sauce is actually worse than having a piece of pork. So given that there is a 3rd option on board a plane - you can have vegetarian (which some very religious Jews wouldn't have either), or even a "fruit plate", this would be the best thing for a religious Jew on board a plane where no Kosher food is available.