Metro Airlines did fly into Galveston from IAH
as well as CLC (Clear Lake City).
In Idaho: Coeur d' Alene, Burley, Gooding have had air service at one time. I have a June '78 AirOregon timetable,and they served 24 cities in Oregon. Today,only 7 Oregon cities receive airline service.
Also Stockton,Concord,Palmdale,Napa,San Rafel,Palo Alto,Santa Rosa,Eureka(Murray Field),Marysville,South Lake Tahoe,Ukiah,Yreka(Siskiyou Co.),Red Bluff,Borrego Springs,Palm Desert,are some California cities IO can think of now that have had airline service. Many in Nevada also,thanks to Air Chaparral in 1980 had service.
Just look through any old OAG and you will see many,many,many cities that had service.
I have an old West Coast timetable that listed an Idaho Falls to Tacoma,WA service with two connections and 11 stops: IDA-PIH-BYI-TWF-BOI
-ALW x fer - PSC-YKM-BFI
-TAC. All in DC-3 comfort!!