Name an item designed to be filled with air

The rarest possible answer — almost no player finds it.

• Inflatoplane— Goodyear built this inflatable airplane for downed pilots in 1956.

Genuinely obscure. Most players never think of it.

• Air beam
• Air caster
• Air expanding shaft
• Air lounger
• Air pogo stick
• Air receiver
• Air ride seat
• Air shock
• Air splint
• Air spring
• Air Swimmer
• Air track
• Air wedge
• Air-cushioned shoe sole
• Airbag helmet
• Airbag vest
• Airplane oxygen mask
• Ambu bag
• Anti-shock trousers
• Avalanche airbag
• Baby neck float
• Balloon bomb
• Balloon catheter
• Balloon helicopter
• Balloon satellite
• Bandoneon
• Barrage balloon
• Biogas bag
• Bladder fiddle
• Bladder pipe
• Boat fender
• Bossaball
• Breathalyzer balloon
• Bungee run
• Buoyancy compensator
• Cage ball
• Combitube
• Concertina
• Cuju ball
• Diving bell
• Double glazing
• Double-end bag
• Draco standard
• Duct balloon
• Emergency flotation system
• Endotracheal tube
• Esophageal obturator airway
• ETFE cushion
• Expansion tank
• Fistball
• Float tube
• Floating cooler
• Foil balloon
• Follis
• Football bladder
• Futsal ball
• G-suit
• Gaelic football
• Gamow bag
• Gas balloon
• Gas sampling bag
• Gas spring
• Gastric balloon
• Gladiator joust
• Harmonium
• Hip airbag
• Horseball
• Hospital air mattress
• Hovercraft skirt
• Human foosball
• Hydraulic accumulator
• Hydropneumatic suspension sphere
• Hyperbaric chamber
• Inflatable airlock
• Inflatable antenna
• Inflatable arch
• Inflatable baby seat
• Inflatable back brace
• Inflatable bar
• Inflatable bathtub
• Inflatable bedpan
• Inflatable boxing gloves
• Inflatable bra
• Inflatable car cover
• Inflatable cervical traction collar
• Inflatable dock
• Inflatable dog cone
• Inflatable footrest
• Inflatable heat shield
• Inflatable heel protector
• Inflatable hunting decoy
• Inflatable jack
• Inflatable kickboard
• Inflatable lumbar support
• Inflatable mandrel
• Inflatable movie screen
• Inflatable nasal pack
• Inflatable oil boom
• Inflatable ottoman
• Inflatable packer
• Inflatable pessary
• Inflatable pet bed
• Inflatable pipe plug
• Inflatable planetarium
• Inflatable pool pillow
• Inflatable radome
• Inflatable rescue walkway
• Inflatable rubber dam
• Inflatable scooter
• Inflatable sculpture
• Inflatable seat belt
• Inflatable sex cushion
• Inflatable sex toy
• Inflatable shampoo basin
• Inflatable space habitat
• Inflatable spray booth
• Inflatable sprinkler
• Inflatable stretcher
• Inflatable tent
• Inflatable wedge pillow
• Intra-aortic balloon pump
• Jumping pillow
• Kamifusen (paper balloon)
• Kayak float bag
• King airway
• Knobby ball
• Koinobori
• Korfball ball
• Laryngeal mask airway
• Lift bag
• Marine airbag
• Massage chair air bags
• Mechanical bull mat
• Netball
• Non-rebreather mask
• Oleo strut
• Otovent balloon
• Packraft
• Paddle float
• Padel ball
• Pallone
• Patient transfer air mattress
• Pneumatic artificial muscle
• Pneumatic caisson
• Pneumatic clutch
• Pneumatic compression sleeve
• Pneumatic de-icing boot
• Pneumatic formwork
• Pneumatic tourniquet
• Pontoon
• Pool island
• Portative organ
• Punch ball
• Rebreather counterlung
• Reebok Pump
• Rescue air cushion
• Rhythmic gymnastics ball
• Rigid inflatable boat
• Shruti box
• Snorkel vest
• Soft robotic gripper
• Soft tennis ball
• Solar balloon
• Sponson
• Stunt airbag
• Surf mat
• Surface marker buoy
• Swim belt
• Tchoukball ball
• Tethered balloon
• Thundersticks
• Tire curing bladder
• Tracheostomy tube
• Wallyball ball
• Water blob
• Water hammock
• Water iceberg
• Water rocket
• Water roller
• Water trampoline
• Wobble cushion

Uncommon — only a minority of players land here.

• Accordion
• Advertising inflatable
• Air cushion
• Air horn
• Air pillows
• Australian rules football
• Bag of chips
• Bagpipes
• Balloon animal
• Balloon car
• Bath pillow
• Bellows
• Blood pressure cuff
• Blow up doll
• Bop bag
• BOSU ball
• Bubble mailer
• Bumper ball
• Buoy
• Dodgeball
• Evacuation slide
• Gaga ball
• Handball
• Inflatable building
• Inflatable chair
• Inflatable costume
• Inflatable hot tub
• Inflatable kayak
• Inflatable military decoy
• Inflatable paddleboard
• Inflatable pillow
• Inflatable slide
• Inflatable sofa
• Kickball
• Life jacket
• Life raft
• Neck pillow
• Parade balloon
• Party blower
• Roundnet ball
• Rugby ball
• Scuba tank
• Sky lantern
• Sleeping pad
• Snow tube
• Space hopper
• Space suit
• Speed bag
• Swim vest
• Tetherball
• Towable tube
• Water polo ball
• Weather balloon
• Windsock
• Zorb

A solid, middling pick shared with plenty of other players.

• Airbag
• Airship
• American football
• Arm floats
• Ball
• Bouncy castle
• Bubble wrap
• Exercise ball
• Helium balloon
• Hot air balloon
• Inflatable boat
• Inflatable pool
• Inflatable toy
• Inflatable tube man
• Inner tube
• Lawn inflatable
• Pool float
• Pool toys
• Soccer ball
• Swim ring
• Tennis ball
• Volleyball
• Whoopee cushion

The most common answer on the board.

• Air mattress
• Balloon
• Basketball
• Beach ball
• Tire