From the Article:

Commercial aviation was just getting off the ground when this photo was taken in 1940. Milwaukee County had opened its first primitive airport in what is now Currie Park in 1919, only 16 years after the Wright brothers terrorized the resident birds of Kitty Hawk, but the focus of attention shifted steadily to what we know today as Mitchell Airport, pictured here.

Milwaukee County began to buy land near the intersection of Layton and Howell avenues in 1926, and commercial planes were soon taxiing down cinder runways on what had once been a seasonally soggy horse pasture.

Scheduled passenger service began less than a year later, when a Northwest Airways three-seater made its inaugural daily flight from Chicago to Minneapolis, stopping in Milwaukee en route. The one-way fare was $50 – nearly $900 in today’s dollars – and the plane cruised at an airborne snail’s pace of 85 miles per hour.

As flying became faster, cheaper and easier, demand soared, and Milwaukee soon needed a genuine passenger terminal. In 1940, with major help from New Deal relief programs, the building pictured here was dedicated at 1011 E. Layton Ave. It served paying passengers, but there was still plenty of room for airline offices, a weather station and a control tower.

Within a decade, rapid growth had made the “new” terminal obsolete. In 1950, Milwaukee County decided to shift the airport’s operations center westward. A state-of-the-art facility opened on the Howell Avenue side of the field in 1955, and it became the nucleus of the sprawling complex familiar to today’s travelers.

Useless for anything but storage, the Layton Avenue terminal was demolished in 1966. Its site was eventually occupied by private hangars, and sleek corporate jets now touch down where biplanes and Trimotors once ruled the runways.