Aero Club is thought to be an exclusive members-only “old boy’s” club on Taylor near Hamburger Mary’s. During this time, it was also known as the Knights of Columbus Club. By all accounts was not a gay club, however, it appears that there were activities related to the gay community.

Per https://rwcn-idwiki-2.restaurantwarecollectors.com/content/aero-club-of-oregon/ :

“The two formed the Aero Club and they stood at SW Park and Taylor until 1998 when they were demolished and replaced with the Paramount Hotel. Notes: From Vintage Portland, the Aero Club was first organized as a private club organized "exclusively for pilots and aeronautics buffs" who were financially able to join. 804 SW Taylor Portland, OR 97205 

The club's building was constructed in 1920 at SW Park and Taylor Streets in Late Gothic Revival style and included an indoor pool that provided training space for the club's swim teams. Among other popular activities at the club were dinners and ballroom dances. 

The club closed in the 1980s, and the building was razed around 1998-99 to make way for construction of what is now The Paramount Hotel.” 

Also, per this post on wordpress.com: 

By Sixis Nine MAY 25, 2012 AT 12:15 AM Aero Club, 1981 | Vintage Portland (wordpress.com)

“My first job was at the Aero Club. A man named Leroy worked as the men’s locker room attendant from forever. I filled in for Leroy for two weeks in the summer of 1976 while he took a vacation. I’m sure Leroy did more, but all I had to do was keep the dry sauna room, steam room, and shower area picked up, and make sure there were lots of clean towels everywhere — oh, and make sure the sauna was stocked with newspapers and magazines, especially porn magazines like “Juggs”, “Stag”, “High Society”, and “Cheri”. Leroy seemed to me to be making pretty good money from the tips he’d get for shining members’ shoes. In those days men were obsessed with keeping a shine on their loafers and their leather dress shoes, and Leroy shined shoes constantly, as did I during those two weeks. Leroy was a master of the art. I was tolerated by the unreasonably kind gentlemen, and they tipped me generously. They must have felt obligated to keep up their routine and probably thought I could do no permanent damage before the Master returned. I continued to work the locker room job on Saturdays for some time.”

Reference: Midtown Blocks Historic Assessment September 2004