FlaK may refer to:

• Preflagellin peptidase, an enzyme
• Anti-aircraft warfare, another term for air defense

• Skywarrior
• Sky-wave
• Skyway Airlines destinations
• Skyway bridge
• Skyway (Buffalo)
• Skyway Enterprises
• Skyway Estates Airport
• Skyway Fishing Pier State Park
• Skyway (George Bush Intercontinental Airport)
• SkyWay Group
• Skyway (Jacksonville)
• Skyway (Metro Manila)
• Skyway (neighborhood)
• Skyways Regional Ex-Airborne Of Sweden
• Skyway, Washington
• SkyWest Airlines flight 5741
• Sky West and Crooked
• Skywest Commons
• SkyWest Flight 5569
• SkyWest, Inc.
• Skywhale
• Skywhales
• Sky Wings Airlines
• Skyworks
• Skyworks Solutions Inc.