a daily round trip "milk run" flight routing of Memphis - West Helena, AR - Stuttgart, AR - Pine Bluff, AR - Little Rock - Hot Springs - Texarkana - Tyler, TX - Dallas - Fort Worth. During the 1960s TTa upgraded their service using Convair 240 piston propliners and later to Convair 600 turboprops In 1968, the airline began operating the first jet service to Memorial Airport using the Douglas DC-9-10 with a daily nonstop flight to Dallas and was also flying direct, one stop DC-9 service to Memphis via Little Rock. Trans-Texas then changed its name to Texas International Airlines in 1969. Texas International (TI) continued to serve Hot Springs with DC-9 jetliners on a daily basis and in 1970 was flying nonstop to Memphis and Texarkana with continuing, direct service to Dallas and Houston. By 1972, TI was operating daily DC-9 jet service from Los Angeles (LAX) to Hot Springs via intermediate stops in Albuquerque and Dallas (Love Field). Central Airlines began service to Hot Springs by 1955 on a new route between Tulsa and Little Rock which made stops in Fort Smith, AR and Hot Springs using Douglas DC-3s and later upgrading to Convair 600 turboprops in the mid 1960s. Central was merged into original Frontier Airlines (1950-1986) in 1967 and continued to serve Hot Springs with Convair 580 and Convair 600 turboprops nonstop to Fayetteville, AR, Fort Smith, Little Rock and Memphis at different times over the years. In 1967, Frontier was flying nonstop to Fort Smith and Little Rock with direct service being operated to Kansas City, Omaha and Denver. Through the 1950s and 1960s Hot Springs was served by three airlines consecutively. In early 1969 there were a total of 13 departures per day, four of them on DC-9 jets (two on Delta and two on Texas International). Delta then discontinued its service to the airport later in 1969. According to the Official Airline Guide (OAG), two airlines were serving the airport in early 1976: the original Frontier Airlines and Texas International with a combined total of seven flights into the airport every weekday with Frontier operating nonstop flights from Fort Smith and Little Rock as well as direct, no change of plane service from Amarillo, Denver, Liberal, KS, Memphis, Oklahoma City and Tulsa with all of its flights operated with Convair 580 turboprops while Texas International was operating nonstop flights from Memphis