I had hoped that FIM would give guidance on why Aer Lingus uses a cello as example booking but can't possibly fit within size guidelines. They copypasta the airline's website. I can't even point this out to FIM in their feedback form. The airline limits to 37" height. A cello case is minimum 52". 🤦🏻♀️
AER LINGUS | FIM
Check Air Lingus's policy regarding musical instruments
fim-musicians.org