If it's being used as a plane hauler, would they still retain a few suitable planes for ASW defence? Given the ships low speed, would that factor limit the selection of available options?
If she is used in the Pacific, where the main effort for the US Navy took place, ASW is not the major concern in the Eastern part of the ocean. The threat from IJN submarines increases in the vicinity of the various bases and anchorages used by the Allied navies further West. There would already be extensive land based aircraft patrolling in those areas.
Also the Langley, not much faster than a Liberty ship, would not be sailing alone but in a convoy or small group escorted by DDs and/or DEs with whatever air patrolling the USN would provide for any valuable convoy either in the Atlantic or Pacific ocean. So I don't think she would be providing her own ASW planes, but they would be there from other sources.