So something like this maybe?
SKYCOACH
Huge vehicle (40 ft. by 10 ft.)
Creature Capacity 1 crew, 24(?) passengers
Cargo Capacity ? tons
Travel Pace 3 miles per hour (24 miles per day)
STR 11 (+0) DEX 8 (-1) CON 11 (+0) INT 0 WIS 0 CHA 0
Damage Immunities poison, psychic
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, incapacitated, paralyzed, petrified, poisoned, stunned, unconscious
Actions
On its turn, the skycoach can take the move action below. It can’t take this action if it has no crew.
Move. The skycoach can move using its magical propulsion.
Hull
Armor Class 15
Hit Points 175
Speed (air) 30 ft.