Boeing Co. Boeing (BA) has confirmed that it will deliver the next-generation Air Force One jets by 2028, even as President Donald Trump has been flying around in a Qatar-gifted Boeing 747 instead of the official presidential aircraft. But here's the catch: the price tag is going up again.

According to a Reuters report on Sunday, Steve Parker, CEO of Boeing Defense, Space & Security, said the 2028 timeline will bring further "cost growth" due to wiring, structural work, and certifications. Still, he insisted the company is "on track for 2028."

Boeing originally won a $3.9 billion contract in 2018 to build the two modified 747-8s that serve as Air Force One. The program is now running four years late and billions over budget, with total costs surpassing $5 billion. That's a lot of taxpayer money for a plane that the president doesn't even seem to want to use.

Speaking of which, Trump has faced a firestorm of criticism from Democratic lawmakers over his use of a $400 million Boeing 747 gifted by Qatar. California Governor Gavin Newsom dubbed it "Air Fraud One," while Senator Elizabeth Warren accused Trump of taking a "joy ride" instead of signing a bipartisan affordable housing bill. Senate Minority Leader Chuck Schumer called the jet a national security threat and a waste of money. Ouch.

Meanwhile, Boeing is also doing other airplane stuff. The company announced a fuel-efficiency and noise-reduction flight-testing partnership with Germany's Deutsche Lufthansa AG Lufthansa (DLAKF) and engine maker Rolls-Royce Holdings PLC Rolls-Royce (RYCEY), using a 787-9 Dreamliner powered by Rolls-Royce Trent 1000 engines. On top of that, Boeing—along with airlines, airports, and unions—is urging lawmakers to pass a $20 billion funding package for air traffic control upgrades. Because why not pile on more spending requests?