Musicians often book two seats on flights so their instruments can be strapped in beside them, rather than placed in hold luggage “for many reasons”, he explained.
But Mr Kanneh-Mason said he and fellow musicians often run into problems with their bookings, and called for British Airways to develop “some sort of protocol that we can refer to when we hit these problems”.
Writing on X, formerly known as Twitter, the 24-year-old said: “So British Airways (and there are other airlines who do this too), shall we sit down and try to work something out, please?”
The 2016 BBC Young Musician of the Year, who also played at Prince Harry and Meghan’s wedding, had performed alongside the Hungarian National Philharmonic Orchestra in Bucharest and was booked in to fly to London Heathrow on the morning of September 20.
“I arrived early at the airport with my cello, with my two confirmed tickets, one for me and one for the cello,” he explained on X.
“I was not allowed to board with my cello and yet the blame was placed firmly on me. No solution was offered, no compensation, just that it was my fault because I had allegedly ‘modified the booking’.”
Mr Kanneh-Mason, from Nottingham, claimed that he had not modified or changed his booking in any way.
He said: “Sadly, this is a common problem for me and my fellow professional musicians who travel with instruments that, for many reasons, cannot go in the hold. Why are there these inconsistencies?”
Later the cellist added that he booked a new flight home that he said cost “three times as much” as the original tickets.
A spokesperson for British Airways said that Mr Kanneh-Mason’s experience was due to “an error”.
“We’ve apologised to our customer for this mistake and are taking steps to help ensure it doesn’t happen again,” the spokesperson said in a statement.
“We are also in direct contact with the customer to resolve the matter.”
Another British cellist Guy Johnston said he had a “similar experience” when he travelled to Austria.
“It’s maddening!” he wrote on X. “I had to pay double the original ticket price from what I remember.”
A French horn player, Lisa Ridgway, also said she had issues checking in to a British Airways flight to Dublin last year.
“My French horn had its own seat. Because it didn’t have a passport associated with it, they had issues checking me in. Took 2 staff with over 20 years experience each, plus a phone call,” she wrote on X.