The U.S. Navy is moving forward with a long-delayed effort to replace the aging fleet of Marine One helicopters that transport the U.S. president, with the first of the new aircraft slated to enter service in 2020.

The Navy’s last attempt to buy a new presidential helicopter ended in 2009, when then-Defense Secretary Robert Gates cancelled a program run by Lockheed Martin Corp after numerous requirement changes threatened to double the cost of the program to more than $13 billion.

On Friday, the Navy issued a draft request for proposals that maps out its plan to buy 25 new helicopters, giving companies until Dec. 5 to respond. It also invited bidders to an unclassified conference to be held the week of Dec. 10, when government officials will answer questions about the proposed terms of the competition.

This time, Lockheed Martin is paired with Sikorsky Aircraft, a unit of United Technologies Corp, offering Sikorsky’s S-92 helicopter.

Lockheed’s partner on the previous program, Finmeccanica SpA unit AgustaWestland, has teamed up with Northrop Grumman Corp, to submit a possible bid based on AgustaWestland 101 helicopter.

Boeing Co said it is also studying a possible bid based on its H-47 Chinook helicopter or the V-22 Osprey tilt-rotor aircraft that it builds with Textron Inc’s Bell Helicopter unit.

The current presidential helicopters are VH-60N “Night Hawks” and VH-3D “Sea Kings,” both built by Sikorsky. The fleet is operated by the Marine Corps, but the acquisition program is overseen by the Navy.

In the draft request, which was posted to a federal procurement website on Nov. 23, the Navy said its acquisition plan aimed to integrate mature communications equipment into an existing aircraft. It said it expected to issue a final draft request for proposals in March 2013 and award an initial engineering and design contract by mid-2014.

“We’re pursuing a technically viable and cost-effective aircraft to replace the current presidential helicopters,” said Navy spokeswoman Kelly Burdick. “No PowerPoint planes.”