The most common and most likely answer to this crossword clue is the 7 plus 5 letter word LANDING STRIP
I've seen this crossword clue in The Times
L
A
N
D
I
N
G
S
T
R
I
P
More clues leading to the result LANDING STRIP
- Runway, one seen between flights, ahead of take-off?
- Take off after arriving from here, paradoxically?
- Small airport has one area upstairs for band
- Where fighter comes in to disrobe on stairhead?
- Runway – one’s seen between flights, ahead of take off
- Stumble on areas upstairs in facility at airport
- Take off after start of flight here?
- At airport and in Heather’s journey
- Runway arrival line has been shortened
- Succeeded in winning holiday that begins and ends here?
Buddy explains!

The straight part
We know that "Runway" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case runway = landing strip.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.