My name is so long that even the initial of my first name plus my last name doesn't fit on a credit card. It never gives problems when buying tickets.
But there is another interesting case for people with long names. This relates to the TSA checkpoints in the US, and electronic boarding passes.
When I buy a ticket, they say "the name on the ticket must match your government-issued ID".
Now my government-issued ID has my very long name on it (actually it covers two lines). This cannot work, so the name on the ticket is shortened to
Flor Verylongname Andmore
But even that is too long for the TSA electronic machine, which spits back (from the bar code) that my name is
Then the jobsworth says "I can't tell if this is you because there is only one letter of your first name". And I say "well... get your boss". And then the boss comes, and I get pulled over to the side, and they um and ah, and then I dig up a paper copy of the itinerary from my bag that has my full name, and they go "ah, that's OK".
It has happened to me that the piece of paper was actually for a different flight (date) to the same destination.
So they check "because they have to", not because they really care. And eventually I make it onto the plane.
Flying over 100,000 miles per year you'd have thought it worth my while to change my name.