IFR Military Abbreviation

Instrument Flight Rules

Plural, Regulations which must be followed when weather conditions do not meet the minima for visual flight.

In-Flight Refuelling

Infrared

 Electromagnetic radiation of wavelengths between 7500 A, the limit of the visible light spectrum at the red end, and centimetric radio waves. 

In-Flight Refueling

Instrument Flying Rules

Instituteument Flight Rules

Instituteument Flight Range

Instrumented Flight Rules

International Fleet Review