Helio Aircraft

Order of Battle · Aircraft manufacturers · United States

Helio Aircraft

Koppen-Bollinger Aircraft Corporation · Helio Aircraft Corporation · Helio Aircraft Company

Two Boston academics built an aeroplane that could take off across a runway and fly under control at 27 mph; the CIA loved it so much that the company later sued the agency for trying to ruin it.

1948Founded
Defunct 1985Status
6Aircraft on record
2Air forces flying its types
Photo: San Diego Air and Space Museum Archive / Wikimedia Commons (Public domain)
CountryUnited StatesFounded1948FoundersOtto C. Koppen, Lynn BollingerHeadquartersPittsburg, KansasStatusDefunct 1985
The story

Helio Aircraft: the company and the aircraft that made its name

Smart airplanes for dumb pilots

Otto Koppen taught stability and control at MIT, and in 1936 he wrote a paper called Smart Airplanes for Dumb Pilots. In 1948 he and Lynn Bollinger set out to build one. Their demonstrator, a rebuilt Piper Vagabond with full-span slats and big flaps, first flew from Boston Metropolitan Airport on 8 April 1949. The production Helio Courier, certified in July 1954, had automatic slats and could stay under control at about 27 mph. At air shows it took off across the runway rather than along it.

The Courier and the secret war

About 500 Couriers were built in Pittsburg, Kansas, between 1954 and 1974. In 1957 a Strato Courier set an altitude record of 31,200 ft over Mexico City. The military Super Courier, the U-10, served with the US Air Force, Army Special Forces and Air America in Vietnam; over 120 were built. Seven Twin Couriers went to the CIA under the cover designation U-5, and 20 turboprop AU-24 Stallion mini-gunships were built, most ending up with the Khmer Air Force.

Lawsuits and revivals

General Aircraft bought Helio in 1969, and in 1974 it went to court claiming the CIA had planned to ruin the business by arranging unlicensed production of the Courier. A revival by Helio Aircraft Ltd built just 18 more aircraft before it was evicted from its factory in February 1985. The rights changed hands several times; since 2019 Helio Alaska has held the type certificate and tooling. Missionary and bush pilots still prize the Courier’s short-field performance.

Two Boston academics built an aeroplane that could take off across a runway and fly under control at 27 mph; the CIA loved it so much that the company later sued the agency for trying to ruin it.Helio Aircraft · verified 2026-10-03
At a glance

Helio Aircraft in numbers

The company

In short
Founded 1948

  • Founded as Koppen-Bollinger Aircraft Corporation in Massachusetts
  • Production plant at Pittsburg, Kansas
  • Bought by General Aircraft Corporation, 1969
  • Last production ended 1985

Production

Best known for
Helio Courier

  • About 500 Couriers built, 1954–1974
  • U-10 Super Courier: over 120 for the US military
  • AU-24 Stallion gunship: 20 built
  • 18 H-700/H-800 built in the 1980s revival

Today

Now
Defunct; type revived by Helio Alaska

  • Helio Alaska holds the Courier type certificate since 2019
  • Couriers still flown by bush and missionary pilots

The numbers

Couriers built
about 5001954–1974
Minimum control speed
about 27–28 mph
U-10 for US forces
over 120
The aircraft

Every notable Helio Aircraft aircraft

Aircraft Role First flight Built Status Note
Helioplane No. 1 STOL demonstrator 1949 1 Retired Converted Piper PA-17 Vagabond; donated to the Smithsonian in 1963
Helio Courier (H-391B and later) STOL utility aircraft about 500 In service Certified July 1954; automatic leading-edge slats
Helio U-10 Super Courier Military STOL liaison and special operations over 120 Retired USAF, Army Special Forces, Air America
Helio H-500 Twin Courier (U-5) Twin-engine STOL aircraft 7 Retired Delivered to the CIA
Helio AU-24 Stallion Turboprop utility and gunship 1964 20 Retired Most went to the Khmer Air Force in 1972
Helio H-700 / H-800 Courier STOL utility aircraft 18 Retired Direct-drive engines and winglets
Who flies them

Helio Aircraft aircraft in the world’s air forces

2 air forces in the Order of Battle fly or flew Helio Aircraft types. 0 of them still have one in service.

Air force In service Formerly flown
Guyana Defence Force Air Corps Helio Courier
Royal Cambodian Air Force Helio AU-24A Stallion
Places, people, records

Where Helio Aircraft built, who led it, what it achieved

Factories

  • Boston Metropolitan Airport · Canton, Massachusetts — First home of the company
  • Atkinson Municipal Airport plant · Pittsburg, Kansas — Acquired July 1956; nearly destroyed by wildfire March 1966

People

  • Otto C. Koppen · co-founder, designer — MIT professor (1901–1991), earlier designed the Ford Flivver
  • Lynn Bollinger · co-founder

Records and firsts

  • Strato Courier altitude record of 31,200 ft over Mexico City, 1957
Timeline

Helio Aircraft, year by year

1948

Koppen-Bollinger Aircraft Corporation founded

1949

Helioplane No. 1 first flight

1954

Helio Courier certified

1956

Pittsburg, Kansas, plant acquired

1957

Strato Courier altitude record

1964

Stallion prototype first flight

1969

Bought by General Aircraft Corporation

1972

AU-24 Stallions delivered to the Khmer Air Force

1974

Production ends; lawsuit against the CIA

1985

Revived company evicted from its factory

2019

Helio Alaska acquires the type certificate

Questions & Answers

Everything people ask about Helio Aircraft

What is the Helio Courier famous for?
Extreme short take-off and landing performance: automatic slats and big flaps let it stay under control at about 27 mph and take off in a few lengths.
Did the CIA use the Helio Courier?
Yes. Couriers flew with Air America in Vietnam and seven Twin Couriers went to the CIA under the designation U-5. In 1974 Helio’s owner sued the agency, alleging it had planned to ruin the business.
How many Helio Couriers were built?
About 500 between 1954 and 1974, plus 18 more in the early 1980s.
Who designed the Helio Courier?
MIT professor Otto C. Koppen, who founded the company with Lynn Bollinger in 1948.

Continue the tour

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Sources & Further Reading

Every fact, checked

Verified 2026-10-03.