There is no single, official motto but there are many mottos associated with the Air Force from different times and places. Those include:
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The current motto of the United States Air Force is Aim High ... Fly-Fight-Win
The motto of United States Air Force Combat Control Team is 'First there'.
United States Air Force's motto is 'Aim High ... Fly-Fight-Win'also ''.
United States Air Force Security Forces's motto is 'Defensor Fortis'.
Air Force Flight Test Center's motto is 'Toward the Unknown'.
Strategic Air Command's motto is 'Peace is our Profession'.
United States Air Force's motto is 'and'.
The motto of US Air Force Tactical Air Control Party is 'Death on Call'.
The motto of the United States Air Force is "Above All".
The motto of Czechoslovak Air Force is 'Air is our sea'.
The motto of Czech Air Force is 'Air is our sea'.
Hellenic Air Force's motto is 'Αἰὲν Ὑψικρατεῖν'.
The motto of Latvian Air Force is 'All for Latvia!'.
Finnish Air Force's motto is 'Qualitas Potentia Nostra'.
Kenya Air Force's motto is 'Tuko Imara Angani'.
Brazilian Air Force's motto is 'Wings that protect the country'.
Uruguayan Air Force's motto is 'Aviation vanguard of the homeland'.
Venezuelan Air Force's motto is 'Spatium superanus palatinus'.
Portuguese Air Force's motto is 'Ex Mero Motu'.