The most common and most likely answer to this crossword clue is the 8 letter word BOARDERS
I've seen this crossword clue in The Daily Telegraph
B
O
A
R
D
E
R
S
Buddy explains!
The straight part
We know that "those getting on plane" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case those getting on plane = boarders.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BOARDERS mean?
BOARDERS noun- A pupil who lives at school during term time.
- Someone who pays for meals and lodging in a house rather than a hotel.
- One who boards a vehicle.
- A sailor attacking an enemy ship by boarding her, or one repelling such attempts by an enemy.
- Someone who takes part in a boardsport, such as surfing or snowboarding.