Answer by taking a quote from the following article:

The Midnight Express was a professional wrestling tag team of changing members, mostly under the management of Jim Cornette. The group started in the early 1980s with Dennis Condrey and Randy Rose (and originally Norvell Austin). The late 1980s saw a new incarnation, consisting of Bobby Eaton and Stan Lane, compete in JCP and WCW and shortly feuding with "The Original Midnight Express" of Condrey and Rose. In the 1990s, the World Wrestling Federation (WWF) combined Bob Holly and Bart Gunn as "The New Midnight Express".

Due to various differences over the direction of the Midnight Express, Cornette, Lane and Eaton also left JCP for a short while, around the time that Ted Turner bought out Jim Crockett and began promoting the federation under the name World Championship Wrestling (WCW). When the issues were resolved, Cornette and the Midnight Express returned to the promotion. In the tournament to determine new World tag team champions, the Midnight Express advanced to the finals before losing to the Freebirds with some assistance from the Samoan Swat Team. They engaged in a feud with the Freebirds and Samoans until the 1989 Great American Bash, where they teamed up with the Road Warriors and Dr. Death Steve Williams to defeat the Freebirds and Samoans in a War Games match.  The Midnight Express soon turned heel as a result of a feud with the Dynamic Dudes (Johnny Ace & Shane Douglas). Jim Cornette duped the Dudes into thinking he wanted to be their manager but then turned on them during their match against the Midnight Express at Clash of the Champions IX in New York. The Dynamic Dudes gained a measure of revenge when the Midnight Express laid out an open challenge for any team for $10,000. After dispatching of a couple of no-name teams, the Express was challenged by the masked Dynamic Duo, billed from Gotham City, who pinned the Express and unmasked as Ace and Douglas. The feud soon lost steam and was forgotten soon after.  After returning to their cheating ways, the Midnight Express started a feud with the up-and-coming team of Flyin' Brian and "Z-Man" Tom Zenk over the United States Tag team titles. The Express won the titles from the young team in early 1990, but lost them to The Steiner Brothers (Rick and Scott) three months later. After a loss at Halloween Havoc 1990, the Midnight Express split up when Jim Cornette and Stan Lane left the federation. For the first time in almost a decade there was no Midnight Express.

What happened in 1989?
They engaged in a feud with the Freebirds and Samoans until the 1989 Great American Bash,