mediumAI↳ cluesBoarding section can refer to class (first class, business class, etc.)
R
O
W
mediumAI↳ cluesBoarding is sometimes organized by row number
G
A
T
E
mediumAI↳ cluesGate is the boarding area/section at an airport
A
I
S
L
E
lowAI↳ cluesSection of a plane, though not specifically a boarding section
If you're stuck on the clue “Airline boarding section”, the most likely
answer is ZONE
(4 letters) — Airlines divide boarding into zones/sections.
Other possibilities include GROUP, CLASS, ROW, GATE.