Related Clues:

• Tire inflater
• Pocket filler?
• You can't live without it
• Bring up, as a grievance
• Type of pressure
• Inner-tube innards
• Gas-station freebie
• Hopefully, it's fresh
• Bubble contents
• Plane peril, ___ piracy
• Refrain
• What you breathe
• It's in circulation
• Plane's place
• Oxygen sources