The Department considers it a violation of 49 U.S.C. 41732 and the air service guarantees provided under this part for an air carrier providing essential air service to an eligible place to overfly that place, except under one or more of the following circumstances:

(a) The carrier is not compensated for serving that place and another carrier is providing by its flights the service required by the Department's essential air service determination for that place;

(b) Circumstances beyond the carrier's control prevent it from landing at the eligible place;

(c) The flight involved is not in a market where the Department has determined air service to be essential; or

(d) The eligible place is a place in Alaska for which the Department's essential air service determination permits the overflight.