Wikipedia's take on ValueJet

The airline went public in June, 1994 after a year of tremendous growth with the addition of 15 aircraft since the first flight in 1993. They became the fastest airline to make a profit in the history of American aviation, earning US$21 million in 1994 alone. In October 1995, ValuJet placed an order with McDonnell Douglas for 50 MD-95 jets (now known as the Boeing 717) with an option for 50 more. To keep costs low, the airline bought many used aircraft from around the world. At the time ValuJet's fleet was among the oldest in the United States, averaging 26 years. In 1995, the airline sued Delta Air Lines and TWA over landing slots.[4]
ValuJet took aggressive measures to hold down operating costs. Its employees were paid well below prevailing market costs. The airline did not own any hangars or spare parts inventories. ValuJet also required pilots to pay for their own training and only paid them after completed flights. It also gave flight attendants only bare-bones training. It also outsourced many functions other airlines handle themselves. For instance, it subcontracted maintenance to several companies, and these companies in turn subcontracted the work to other companies. Whenever delays were caused by mechanics, ValuJet cut the pay of the mechanics working on that plane. [5][6]
Safety problems

In August 1995, the Department of Defense (DoD) rejected ValuJet's bid to fly military personnel. In a scathing report, the DoD cited serious deficiencies in ValuJet's quality assurance procedures.[5]
The Federal Aviation Administration's (FAA) Atlanta field office sent a memo on February 14, 1996, to Washington, D.C., stating that "consideration should be given to an immediate FAR-121 re-certification of this airline" - in other words, the FAA wanted ValuJet grounded. ValuJet airplanes made 15 emergency landings in 1994, 57 in 1995, and 57 from January through May 1996. In February the FAA ordered ValuJet to seek approval before adding any new aircraft or cities to their network, something the industry had not seen since deregulation in 1979. This attempt at removing ValuJet's certification was "lost in the maze at FAA" according to NTSB Chairman Jim Hall.[7] By this time, ValuJet's accident rate was not only one of the highest in the low-fare sector, but was more than 14 times that of the legacy airlines.[5]