Will airlines refuse boarding from Manchester to Bangkok if I plan to stay for 80 days on a visa exemption?

Never had any issues with Emirates bu Qatar were very officious, asking a lot of questions, this was a few years ago.

Last two I flew with Qatar, they flagged my passport on check in to see the return flight details and to check my visa.

i go for 4 5 mth every winter for yrs they havent asked me once .!!.and i been on many airlines,they used to ask if u had a visa now n then but now its 60 on entry and u can extend it shouldnt be an issue

Just run one of the fake itineraries from those sites.

Be very surprised if your airline would have an issue.

You can buy a ticket from onward travel for around £12, but I've just bought a genuine ticket (which I won't use) from Bangkok to KL for £26 which can't be questioned

Do a multi entrance visa online

Most of them will want return/onward travel within 60 days

Depends, some might.

I got questioned before I could fly.

Will airlines let you book a 90 return ticket please ?

Emirates will ask .

Yes some will. Some won’t. So you’ll get conflicting answers here. Some will say “I’ve been to Thailand 500 times and I’ve never been asked”, to others saying “I got stopped boarding until I bought a ticket out”.

Call your airline to ask their policy or buy an “onward ticket” from the plethora of companies that will sell you one for about $15.

Immigration almost certainly won’t care as they know you can get an extension.