Files in the folder "airport.rpf" go to:  

GTAV > mods > x64l.rpf > levels > gta5 > _cityw > airport_01 > airport.rpf


Files in the folder "ap1_03.rpf" go to: 

GTAV > mods > x64l.rpf > levels > gta5 > _cityw > airport_01 > ap1_03.rpf


Files in the folder "ap1_lod.rpf" go to:  

GTAV > mods > x64l.rpf > levels > gta5 > _cityw > airport01 > ap1_lod.rpf