American Airlines is gearing up to become the first US airline to resume commercial passenger flights with the Boeing 737 Max after the plane’s 20-month ban was lifted. The company has completed a test flight with media onboard — a short 45-minute trip from Dallas, Texas to Tulsa, Oklahoma — as part of a public relations campaign before it resumes commercial flights on December 29th. Boeing’s 737 Max planes were grounded around the world in March 2019 following two fatal crashes within a span of five months.

Investigators determined that Lion Air flight 610 and Ethiopian Airlines flight 302 crashed due to, among a few factors, a sensor that sent wrong information to the flight control system. Boeing had to rewrite the plane’s software, update its manuals and conduct key flight safety tests before the FAA cleared the 737 Max’s return to service.

According to Reuters, Boeing set up a 24-hour “situation room” to monitor every Max flight around the world to keep an eye on everything that happens, even if they’re only routine glitches. American Airlines will also note on their website if a flight will use the 737 Max. Both American and Southwest will allow passengers to rebook their flights without paying a fee if the original one they booked was on a Max, as well. If reports are correct, Ryanair trusts Boeing to have done everything it could to fix the plane’s issues. The budget airline is reportedly set to order 210 737 Max planes, more than double its original order of 75 jets.