American Airlines revised its rules in response to a 40 per cent rise in requests for support animals on board between 2017 and 2018.

The airline said untrained animals “can lead to safety issues for our team, our customers and working dogs onboard our aircraft”.

Emotional support spiders, insects, snakes and reptiles are also off-limits under the new restrictions, as well as any “animals with tusks, horns or hooves” with the exception of trained miniature horses.

Passengers will also be expected to give at least 48 hours’ advance warning before travelling with an emotional support animal.