[1] The following year, he received further training with the 550th Tactical Fighter Training Squadron at Luke Air Force Base before being assigned to the 58th Tactical Fighter Squadron at Eglin Air Force Base.
In 1983, he returned to Luke Air Force Base as an instructor with the 555th Tactical Fighter Training Squadron.
During this time, he oversaw Air Reserve Component deployments taking part in Operation Northern Watch.
The following year, he became Director of Operations of the Colorado Air National Guard.
Lassen later served as Director of Staff of the Joint Forces of the Colorado National Guard.