At the request of Mahlon Sweet, the original Eugene Air Park was built in 1919 at what is now the southeast corner of West 18th Avenue and Chambers Street (44.039°N 123.116°W / 44.039; -123.116). This first airstrip took care of all aviation operations until the modern Mahlon Sweet Field opened in 1943. The original site ceased operations in the summer of 1956.

During World War II, the airfield was used by the United States Army Air Forces. The December 1951 C&GS diagram shows three runways forming an asterisk: the 026-deg runway was 5,229 feet (1,594 m) in length, the 111-deg was 5,205 ft (1,586 m), and the 158-deg was 3,999 ft (1,219 m).

Historical service

United Airlines was the first airline to serve Eugene. In June 1944, they began Douglas DC-3s and Convair 240 service, which flew to Portland, Seattle, Los Angeles, and San Francisco with various stops en route. United eventually upsized to larger aircraft, which included the Boeing 727-100s, 727-200s, 737-200s, 737-300s, and 737-500s into the airport nonstop to Denver, Los Angeles, San Francisco, and Portland.

West Coast Airlines began Douglas DC-3 service to Eugene in 1947. Later West Coast operated Piper Navajos, Fairchild F-27s, and Douglas DC-9-10s to the airport before merging with Bonanza Airlines and Pacific Air Lines to form Air West in 1968. Shortly before the merger, West Coast was operating DC-9s to San Francisco via Medford and nonstop to Portland continuing to Seattle (Boeing Field), Boise, and Salt Lake City.

Air West was renamed Hughes Airwest in 1970 with each airline serving Eugene with Douglas DC-9-10s and McDonnell Douglas DC-9-30s. In summer 1968 Air West was flying Spokane-Pasco-Yakima-Portland-Eugene-Medford-San Francisco-Fresno-Las Vegas with a DC-9 and had a nonstop DC-9 to San Francisco. By summer 1980, Hughes Airwest had become all-jet and was flying nonstop DC-9s to Los Angeles, San Francisco, Seattle, Boise and Pasco with direct DC-9s to Denver, Tucson, Redding, Redmond, Klamath Falls, and Yakima.

In 1970 Alaska Airlines flew the Boeing 707 to Eugene for flights to Russia via Portland, Seattle and Anchorage.

The original Frontier Airlines began a pair of Boeing 737-200 one stop direct flights to Denver via Salt Lake City in July 1979. That December, Frontier rerouted its Denver service via a stop in Boise.

Eureka, CA-based commuter air carrier Century Airlines began flights to Crescent City, Eureka, Portland, Sacramento, and San Francisco out of Eugene in December 1979 using De Havilland twin otter and De Havilland dash 7.

Portland, Oregon-based commuter air carrier Air Oregon began serving the airport in the late 1970s and by 1981 was operating Fokker F27 Friendship and Fairchild Swearingen Metroliner propjets on flights to Portland, Seattle, San Francisco, Sacramento, Reno, Eureka, Redding, Medford, Redmond, Pendleton, and North Bend.

Republic Airlines acquired Hughes Airwest in September 1980 and continued to operate DC-9s to the airport but reduced the frequency formerly operated by Hughes Airwest to Los Angeles, San Francisco, Seattle, Pasco, Yakima, Redmond, and Klamath Falls, and ended all flights to Boise and Denver. During summer 1984, the airline had just two nonstop routes to San Francisco and Portland, and by spring 1985, Republic had left Eugene.

Horizon Air acquired Air Oregon in 1981 and began serving Eugene with flights to Portland, Seattle, and other destinations with Fairchild F-27s and Fairchild Swearingen Metroliners. Horizon Air has continued to serve the airport for 35 years.

In fall 1984, Cascade Airways began serving the airport with BAC One-Elevens, HS-748s and Beechcraft 1900Cs. Cascade operated BAC One-Elevens nonstop to Portland and Medford, and also flew the British twin jet direct to Seattle, Spokane, and Calgary from Eugene.

In 1985, American Airlines began direct, one stop McDonnell Douglas MD-80 and Boeing 727-200 service to Dallas/Fort Worth and Chicago via Portland on July 2.

Also in 1985, Cascade Airways was continuing to operate HS-748s and Beechcraft 1900Cs to Portland and other cities after ending its BAC One-Eleven service to the airport.

Pacific Southwest Airlines (PSA) began three BAe 146-200 flights a day to San Francisco in December, 1985.

On August 24, 1986, the original Frontier Airlines ceased operations and filed for bankruptcy, ending its flights to Denver.

Continental Airlines began Boeing 737-300 service to Eugene in April 1987, picking up Frontier Airlines' previous service to Denver. Frontier's service to the airport ended when the airline filed for bankruptcy the previous year and was acquired by Continental's parent company, the Texas Air Corporation.

After its acquisition of Pacific Southwest Airlines, USAir (later renamed US Airways) flew BAe 146-200s from the airport in 1989 to Los Angeles, San Francisco and Medford.

Also in 1989, United Express operated by North Pacific Airlines was flying Embraer EMB-120 Brasilias and BAe Jetstream 31s to Portland and Seattle.

American Airlines began service in 1985 with two daily McDonnell Douglas MD-80 flights to Portland, one continued onto Chicago and the other to Dallas/Fort Worth.