Some early Millinocket pilots were Merle Fogg, who was not from Millinocket but used the ballpark as an airfield more than a decade before the airport was completed. The first hometown flier was Pat Violette, who flew his own Curtis Robin from 1937 until he joined the army. John Luke, Paul Michaud, Binkie LePage, and Bob Steeves learned to fly at the Rockland Flying School, and flew in Millinocket for a time. Soon the Millinocket Aero Club was formed, its nine members including Angus Bears, Gene Betterly, Chet Crawford, Charlie Eustis, Bob Laverty, Bob Mott, Nook Noyes, Charles Turner, and John Walsh.
The Katahdin Avenue Schoool was built in 1931 on the site of the original Millinocket High School. It contained eight classrooms, with a capacity of 320 students. Originally a one-story brick building, additional classrooms and office spaces were added in the 1960s. The building was demolished in 2003.
The Bangor and Aroostook Railroad made improvements to its Millinocket facilities in 1938, raising the railroad yard eleven to thirteen feet, extending it north as far as the Iron Bridge. The railroad station itself was moved across the tracks and turned around, and built an underpass crossing Bates Street, so that the road to the station no longer went to the end of Katahdin Street.
This opened up new areas for housing along Bates Street.
The short streets on the Highland Avenue plateau dipped to cross Katahdin Avenue, which was the original lifeline. Colby Street, which had opened very early for the building of the Catholic Church, now crossed Katahdin Avenue and rose to join the new School Street. With a sharp turn off Katahdin, this street moves northward behind the Congregational Church until it becomes a dead end where a sand bank drops to the flat area below.