Uncertain future for Army's future helicopter.

• Position: From the National Defense Blog

The Pentagon's plan to acquire a new family of helicopters once again is up in the air. The military intends to continue to fund rotary-wing research and testing programs, officials said, but it cannot yet predict if or when it will have funds to buy new aircraft to replace the current fleet.

Like every other modernization program in the Defense Department, new helicopters have to compete for funding within a pool of shrinking dollars. Officials said the military services are having to trade off new weapon systems to fund their payroll.

"The budget environment is very difficult," said Jose M. Gonzalez, deputy director of land warfare, munitions and tactical warfare systems at the Defense Department.

The helicopter modernization effort known as "future vertical lift" got under way in 2009. The goal is to design and build a family of helicopters that would replace the current fleet of Black Hawks, Apaches and Chinooks by...