Boeing Co (NYSE:BA) has announced in conjunction with the U.S. Air Force the successful launch and first test flight of the new KC-46A refueling tanker on Friday. According to a report from Business Finance News, the flight took place in Boeing’s home state of Washington and lasted for four hours, flying from Paine Field in Everett to Boeing Field in Seattle.

The flight on Friday came after multiple months of delays and cost restructuring, with overruns over $1 billion. The flight was supposed to happen in December 2014, but was delayed multiple times until its eventual launch this September.

According to Ronald Johnston, the KC-46 Test and Evaluation chief pilot, the tanker gave a stunning performance during its maiden voyage. The tanker will replace the older KC-135, which has been the Air Force’s main tanker for decades. The KC-135 has been in service since 1964 and has been increasingly costly to maintain throughout its full functioning life, slated to end in 2040.

According to Boeing KC-46 vice president and program manager, Tim Peters, “This is an aerospace industry first and the culmination of a lot of hard work by the team, including Boeing, our suppliers, and the U.S. Air Force.”

The crew of the tanker will now conduct a post-flight inspection and arrange the plain according to USAF standards before it takes off for its next run of test flights. By the end of the year, the KC-46 should be in full use refueling planes from The U.S. Air Force and coalition forces.

The test flight brought the tanker to an altitude of 35,000 feet, and cost an estimated $46.21 billion. The company plans to manufacture 179 additional KC-46 craft, which will be used to not only carry fuel but cargo, passengers, and patients as well.