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Many of the international airlines I have used (including United,
British Airways, etc) do provide gluten-free meals if ordered in
advance. I used to reliably get a great meal (often better than
my husband who had the regular meal), but over the last year or so
I've found that more and more often I was getting something which
wasn't totally GF or else was very tasteless. It got to the stage I
don't bother ordering a special meal now - I eat what I can from
the ordinary menu and take my own snacks. You just have to make
sure you eat or discard any snacks you take before entering your
destination country. It's definitely worth talking to the airline
though before you travel - they have a varied list of "special"
diets available.

Shonagh Hopkirk