Slotted above the Loadstar and below the Paystar and Transtar conventionals introduced after it, the Fleetstar was the first truck line that International designed specifically for vocational use.

The Fleetstar line was larger than the Loadstar (International's medium duty lineup during this time) and smaller than the Paystar (severe service) and Transtar (primarily semi-tractors).

There were Cummins, Detroit Diesel, and International Harvester built engines available in larger sizes than those of the Loadstar line.

Frame rail and axle sizes were generally larger than their smaller cousin, and were of the completely straight design for strength.

Their name is correct in that many were purchased as fleet trucks, and usually lacked the flash and comfort of the more custom Transtar series.