U1

• 1924 United States Army Air Service aircraft designation system
• 1962 United States Tri-Service aircraft designation system
• 1U (disambiguation)
• Apple U1
• Avro 504
• De Havilland Canada DHC-3 Otter
• Frankfurt U-Bahn
• German submarine U-1
• Gitaroo Man
• HDMS U-1
• LNER Class U1
• Munich U-Bahn
• Nuremberg U-Bahn
• Oberursel U.I
• SM U-1 (Austria-Hungary)
• SR U1 class
• Secure_Digital
• Soviet Union military aircraft designation systems
• U-1-class submarine (Austria-Hungary)
• U1 (Berlin U-Bahn)
• U1 (Hamburg U-Bahn)
• U1 (Vienna U-Bahn)
• U1 Technology
• U1 spliceosomal RNA
• UI (disambiguation)
• Unemployment
• Yuvan Shankar Raja
• unitary group