Actually, Dan-Air call were not so simple
Positioning flights usedcthe number 99 followed by the last two letters of the aircraft reg. Eg 99victorgolf.
The only other use of alpha numerics was an experiment in 1982, all letters of the alphabet were used except A and D.
1st letter was B then a 4 denoting a 1-11 or a 6 denoting a 748. So 24 letters used. Eg DA001 B6BB, DA024 B6BZ. DA025 C6BB, DA048 C6CZ.
These were the only examples of alpha numerics used by Dan