The nation's armed services could be unionized "within five years" if "we keep going as we have been going," Gen. David C. Jones, Air Force chief of staff, warned in an interview.

He said the continual talk about changing everything from commissary privileges to retirement benefits has developed a deep sense of uncertainty in military people about the future,

"There is a feeling that no one is interested in looking after the troops," Jones said in trying to identify the unprecedented appeal of unions to military men and women.

"It's the feeling that the senior sergeants' hands are tied; that the majors' hands are tied; that the colonels' hands are tied; that the generals' hands are tied" as the big decisions are being made in Washington.

Jones disputed the theory that the appeal of unions would evaporate if military leaders redressed grievances in the lower ranks. "It's not the privates and the basic airmen who are writing letters to the editor" protesting perceived changes in their lives, "It's the sergeants."

The Air Force general said that the perception among service people that the military is no longer capable of taking care of its own comes when career expectations were never higher.

"There's been a change" from apappealing military to serve their country to portraying the service as a good place to work. Jones adi. He dated the turnaround from the 1970 Gates commission report, which gave the rationate for an all-volunteer force.

"Once you go to an occupation as the motivational basis" for joining the military, Jones said, "just another job, you can't pay enough to keep people from having concerns about the life and the rest."

The Air Force plans to back away from emphasizing occupational betterment in its future recruiting, Jones said, and place more stress on the military. the Air Force has been the most successful service in terms of attracting volunteers since the draft ended in 1973.

But he said the key to undercutting the appeal of military unions is to assure service people that they are not about to lose everything.

"The problems are not what has actually happened" to military people, he continued, but their "perceptions of what might happen. Every day in the trade journals they read that retirement is being changed; that commissaries may be phased down. People are very uncertain."

Jones stressed he is not against unions outside the military and does not believe that military benefits are inviolate. Instead, he urged that any changes in military benefits be postponed until after the commission President Carter has promised to appoint studies them.

What has happened up to now, Jones complained, "is that every bureaucrat has gotten his finger into the pie and there has been no cohensiveness" in reaching judgements on what military benefits should be.

Any changes in these benefits, he said, "should be done by surgery as opposed to cancer."

Although today "I feel the overwhleming majority" of service people would reject unionization, Jones said, the tide could change very fast.

"If we keep going as we have been going" and fail to clear up the uncertainty service men and women feel about their future, Jones said, unionization of the military "could happen within five years." Military unions, he added, "May well be inevitable."

Jones' assessment is the most pessimistic one yet voiced publicly by any member of the Joint Chiefs about the possibility of staving off unions.

Currently, the American Federation of Government Employees (AFL-CIO) is polling its members to see if they want to try to unionize the 2.1 million service men and women on active duty.