Decoding the Alphabet: Why U.S. Military Aircraft Names Use Letters

Designations like B-17, P-51, and F-86 evolved from complex acronyms to simple purpose identifiers.

Meg Godlewski

Wednesday, April 15, 2026 at 09:00 AM ET

Verified

Edited By:

Travis Tingle

B-17 bomber [Credit: FLYING Archive]

Key Takeaways:

The U.S. military uses letters in aircraft names to identify the primary purpose or role of the aircraft.
The naming system evolved from complex multi-letter designations (e.g., "PW" for pursuit, water-cooled) before 1924 to simpler, single-letter codes like "P" for pursuit.
During World War II, common designations included "B" for bomber, "P" for patrol, and "PT"/"AT" for trainer aircraft.
In 1948, the newly formed U.S. Air Force changed the "P" (pursuit) designation to "F" (fighter) to reflect more specialized aircraft roles, with existing aircraft updated accordingly.

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Question: Why did the U.S. military start using letters to name the airplanes it uses? For example B-17, P-51, F-86?

Answer: The letters are the military way of identifying the purpose of the aircraft. Prior to 1924 military aviation had multiple designations for classification of fighter aircraft. For example, “PW” stood for pursuit, water-cooled. So many letters became cumbersome and by 1924 the “P” for pursuit stood alone.

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During World War II, “B” stood for bomber, “P” for patrol, “PT” for primary trainer, “AT” for advanced trainer.

In 1948 the newly formed U.S. Air Force changed the “P” designation to “F” for fighter, reflecting the more specialized roles of the aircraft. Existing aircraft still in military use simply swapped out the “P” for “F.”

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