airline (n.)

• aeronautics
• airway
• astronautics
• aviation
• axis
• ballooning
• beeline
• chord
• corridor
• cut
• cutoff
• diagonal
• diameter
• edge
• flight
• flying
• gliding
• lane
• normal
• path
• perpendicular
• pilotage
• radius
• sailing
• sailplaning
• secant
• segment
• shortcut
• side
• soaring
• straight
• straightaway
• tangent
• vector
• winging