Apparently it's not illegal,
I just googled. Someone said they were. There have been calls to make them illegal but the law is on the side of the nuts.

However I get the impression it's typical for them to be served as standard on all American flights, not a custom I think we have in Europe, but I don't fly much myself so I couldn't say. The last time was about 10 years ago, Al Italia, they do nice cheese and salami sandwiches on their flights.
( Moon Girl Technologies horrendous beanbag, Sun 4 Dec 2011, 16:43, 4 replies)

I fly a few times a year in Europe, and the peanuts stopped more or less completely in the late 90s. I don't know why, possibly allergy reasons, or the choking hazard. Now usually they serve savoury snacks, the most common I find are these little crackers that taste like mini cheddars.
(tyrellsOwl, Sun 4 Dec 2011, 17:26, closed)

I recently flew to Oz from London and back
With Air Malaysia and can confirm that they offered peanuts on all four flights. I declined them, not because I'm allergic to them or I'm a terrorist, but because I'm allergic to other nuts and don't like to run the risk with trace amounts of the bad stuff.
(Rilux might be pregnant and has bum-aids, Sun 4 Dec 2011, 17:32, closed)

i'd only fly if i had no alternative
it really disorientates me
( Smash Monkey lowering the tone of the whole internet, Sun 4 Dec 2011, 20:17, closed)

don't do a barrel roll

( Moon Girl Technologies horrendous beanbag, Sun 4 Dec 2011, 20:29, closed)

Conspiracy?
Bloody peanut lobbyists controlling the food we're fed on aeroplanes...
( Hunter Stockton was murdered by a bicycle wielding axolotl,.,.,.,., Mon 5 Dec 2011, 11:05, closed)