Is it permissible for me to combine and shorten my Maghrib and Isha prayers if the Maghrib adhan is called while I am on my way to Dammam Airport, which is 75 km away from me, to travel to Jeddah?

If you leave the populated area of your village heading towards Jeddah, you are permitted to shorten and combine prayers, because the distance between your village and Jeddah is a travel distance. What you mentioned, that the distance to Dammam Airport is less than the travel distance, does not affect this, because your intention is to travel to Jeddah.

Therefore, if the Maghrib (sunset) prayer call is made while you are on the road, you are permitted to pray Maghrib at its time, combining it with Isha shortened, or to delay Maghrib and pray it with Isha as a delayed combination, shortening Isha.