Mr Aikman was booked to travel from Edinburgh to Paris for his honeymoon with Air France, but received a letter telling him he wouldn’t be able to fly.
The airline told Mr Aikman that the chair - which he needs to get around - would not fit in the plane’s hold.
The letter read: “In response to your request I regret to inform you that the dimensions of the electric wheelchair are too big to transport on the aircraft that is operating your flight.”
Mr Aikman, who launched Gordon’s Fightback after being diagnosed with MND in 2014 and has raised more than £400,000 for research into the condition, posted a picture of a letter from Air France on Twitter.
It prompted messages of support from other Twitter users, including Scottish Labour leader Kezia Dugdale, who tweeted: “Hey, @AirFranceUK, all this guy wants to do is go on his honeymoon. What can you do to make that happen?”
Mr Aikman has been trying in vain to get hold of the airline’s PR department but has so far received no response.
Writer and campaigner Talat Yaqoob tweeted: “Dear @AirFranceUK simple really: 1. Arrange alternative transport. 2. Refund. 3. Donate to gordonsfightback.com.”
Budget airline easyJet came to the rescue, with Mr Aikman posting a photo of his wheelchair being loaded onto an easyJet aircraft.