Title 18 USC 926A is supposed to protect one while traveling though states in a car. It has nothing to do with flying. It has nothing to do with driving to/from the airport in your state of residence or from/to the airport in your destination state. There is a reason why 18 USC 926A is called the "safe passage" provision of the Firearm Owners' Protection Act of 1986.
Your post was irrelevant.
Correct. 49 CFR 1544.203 is what you want for flying with a firearm:
https://www.law.cornell.edu/cfr/text/49/1544.203
(f)Firearms in checked baggage. No
aircraft operator may knowingly permit any
person to transport in checked baggage:
(1) Any loaded firearm(s).
(2) Any unloaded firearm(s) unless -
(i) The
passenger declares to the
aircraft operator, either orally or in writing before checking the baggage that any firearm carried in the baggage is unloaded;
(ii) The firearm is carried in a hard-sided container;
(iii) The container in which it is carried is locked, and only the individual checking the baggage retains the key or combination; and
(iv) The
checked baggage containing the firearm is carried in an area that is inaccessible to passengers, and is not carried in the flightcrew compartment,.
(3) Any unauthorized
explosive or incendiary.
(g)Ammunition. This section does not prohibit the carriage of
ammunition in
checked baggage or in the same container as a firearm. Title
49 CFR part 175 provides additional requirements governing carriage of
ammunition on aircraft.
49 CFR 175.10 covers ammunition:
(8) Small arms
ammunition for personal use carried by a
crewmember or
passenger in checked baggage only, if securely packed in
boxes or other
packagings specifically designed to carry small amounts of
ammunition.
Ammunition clips and magazines must also be securely boxed. This paragraph does not apply to
persons traveling under the provisions of
49 CFR 1544.219.
The reason 18 USC 926A largely does not apply when flying is because the airport where you leave from is your state of origin, the airport where you arrive is your destination state. 18 USC 926A does not cover you in either your state of origin or your destination state, it only covers you in the states in between those two.