Engineers designed the model 24 to accept up to the full 13,500 pounds (6,100 kg) gross weight permitted by FAR-25 standards.

From May 23 to 26, 1966, a Learjet 24 flew around the world in 50 hours and 20 minutes flying time as a demonstration of its capabilities.

[1] Different variants were the 24A, B, C, D, E and F, with changes of takeoff weight, in-fuselage fuel tank, range, cabin and engines.

In 2013, the FAA modified 14 CFR part 91 rules to prohibit the operation of jets weighing 75,000 pounds or less that are not stage 3 noise compliant after December 31, 2015.

Improved variant, powered by two 2,950 lbf (13.1 kN) thrust General Electric CJ610-6 turbojet engines, and 13,499 pounds (6,123 kg) maximum take-off weight.

Similar to Learjet 24C, however by changing surface tanks range and takeoff weight were increased to 6,129 kilograms (13,512 lb).

On April 15, 1977, the FAA approved extended ceiling to 51,000 feet (16,000 m), the highest level then achieved in civilian aviation.

Mainly used by private individuals and corporations, one aircraft was used by NASA as the Learjet Observatory [de].