According to White House officials, the Trump administration has agreed an informal deal worth $3.9 billion with Boeing to build a modernized fleet of presidential aircraft.

White House spokesman Hogan Gidley said Tuesday that the agreement would save taxpayers $1.4 billion from the original estimate for two presidential aircraft and the development program associated with purchasing and outfitting them.

The US aircraft company confirmed the deal in a message on Twitter, saying that "president Trump negotiated a good deal on behalf of the American people."

"Boeing is proud to build the next generation of Air Force One, providing American Presidents with a flying White House at outstanding value to taxpayers," Boeing added.

Costly symbol of US might

The legendary Air Force One jets are light blue and white liveried, with "United States of America" emblazoned on the fuselage and an American flag on the tail. But the current models are nearing the end of their 30-year lifespan.

In December 2016, Trump lambasted the cost of the iconic aircraft as "ridiculous," saying Boeing was planning on spending $4 billion on the planes. He threatened to cancel the contract if costs were not brought down.

Read more: Trump lashes out at Boeing over future of Air Force One

But much of the costs for the presidential plane come from pricey and complex modifications required to turn the aircraft into the flying fortresses. The planes are equipped with numerous security and defensive measures, most of which are top secret, as well as the ability to refuel in flight.

Boeing at the time pledged to control costs on the planes. Although details of the new contract were not immediately available, the US Air Force already said last year it had saved some money after Boeing agreed to deliver and refit two 747 jets originally bound for Russia.

uhe/jd (AFP, dpa)