Air Transport International, Inc. (ATI) is an airline based in Wilmington, Ohio, United States. It operates worldwide cargo and passenger charter service for the express package industry (notably, Amazon) and freight forwarders, as well as for the United States Department of Defense. It also wet-leases aircraft. Its main base is Wilmington. It is part of the Air Transport Services Group (ATSG).

ATI's origins are complex. It is often (including on its own website) identified with Interstate Airlines, a 1980s cargo airline, but while there was a connection there was no corporate continuity. Interstate liquidated in the late 1980s after a severe business reverse and its owner bought ATI, a separate carrier, and operated it from former Interstate facilities with former Interstate aircraft. In 1994, ATI merged with another cargo airline, International Cargo Xpress dba International Charter Xpress (ICX). ATI then went through 1998 Chapter 11 bankruptcy and changed owners at least thrice, including once-prominent air freight company BAX Global and since 2007, ATSG. In 2013, ATSG merged a sister airline, Capital Cargo International Airlines, into ATI.

Two organizations competed to fly parts for Big Three automakers after Universal Airlines collapsed in May 1972: Zantop International Airlines (ZIA) and Air Traffic Services Corp. (ATSC; not to be confused with ATI's current owner, ATSG). Founded by David M. Clark (previously at Universal and predecessor Zantop Air Transport) and like ZIA, headquartered at Willow Run Airport near Detroit, ATSC hired airlines to fly parts and provided aircraft to some of those airlines through a related company, Plymouth Leasing. ATSC gave significant business to nascent carriers Evergreen International Airlines and Rosenbalm Aviation in the mid-1970s. ATSC gained national attention in 1979 when reporting showed that in the early 1970s ATSC contracted with Intermountain Aviation and Southern Air Transport, later revealed to be Central Intelligence Agency (CIA) controlled. Clark said he didn't know, but he also said the CIA offered him a job. ATSC's revenue was reported at $50 million/year (over $220 million in 2026 terms).

The 1977 Air Cargo Deregulation Act freed the US domestic air freight market. In 1978, ATSC founded Interstate Airlines (originally U.S. Airways), operational by year-end 1979. Interstate was originally a Convair 580 operator (see Fleet), the aircraft owned by Plymouth Leasing or ATSC, several flying for each of Purolator and Emery. It graduated to Lockheed Electras, Boeing 727s and Douglas DC-8s (see Fleet). The airline was known for flying thoroughbreds, including Secretariat. In 1983, its main commercial customer was Emery and it had 13 727s based in Dayton. The airline also operated for the USAF Logair program. By 1987, Interstate was one of four main contractors for United Parcel Service (UPS), flying packages on UPS-owned aircraft along with Evergreen, Orion and Ryan. ATSC and Interstate moved headquarters from Michigan to Little Rock, Arkansas in 1983 but in 1987, UPS's Louisville hub was Interstate's main base with about 300 (out of about 400) employees based there.

Interstate was interested in passenger service, at one time hiring Mark G. Morris as a consultant on a passenger project. Morris later launched St. Louis-based Air One, which operated all first-class 727s (see picture) from April 1983 to an October 1984 bankruptcy. In 1986 ATSC hired Morris and in February 1987 Interstate merged with the remains of Air One. But in August 1987, UPS announced it would directly operate its aircraft by the end of 1988. This stripped Interstate of 80% of its business and stranded assets like a Little Rock training center, leading Interstate to declare bankruptcy in October. Starting 1988, Interstate liquidated under Chapter 11.

Air Transport International first certificated in 1981; Duane Zantop (majority owner of ZIA) owned 50%. ATI operated intermittently; the Civil Aeronautics Board said it was not operating as of March 1983, but Federal Aviation Administration (FAA) reports show ATI operations in 1984. It certificated a second time in 1986–1987. ATSC's owner bought 50% of ATI in 1988 and operated it from Interstate's former facilities in Little Rock. But Interstate dissolved, it did not merge into ATI. Of the initial ATI fleet, three of four DC-8s were ex-Interstate. As nearby photos show, the initial ATI livery was derivative of the Interstate livery.

International Cargo Xpress dba International Charter Xpress (ICX) (ICAO: ICX, call sign: INTEX), certificated in 1992, was another DC-8 operator under common ownership with ATI. Incorporation records show ATI and ICX merged in November 1994. Three months later, ATI suffered the destruction of its third DC-8 within four years, two of the three crashes fatal (see Accidents and Investigations). The National Transportation Safety Board investigation called out the company and the FAA for insufficient oversight, noting FAA inspector's supervision was inadequate and that he was consumed with the administration of merging the two certificates.

David Clark remained owner of ATI in 1995. However, by 1997 the airline was in financial trouble and up for sale. 50% of the airline's 1997 revenue was military. The winning bidder was freight company BAX Global, for which, in 1998, ATI was flying 12 aircraft. BAX had earlier decided to start its own carrier, but was able to buy ATI out of Chapter 11 for $27 million ($54 million in 2026 terms) in April 1998. BAX replaced senior management.