It had to happen, of course. The wall protecting us was too thin. I mean, how hard could it be to devise a way of making in-flight cell phone calls without interfering with an airliner's navigation system?

And now it's practically here. Airbus, American Airlines and some telecom firms have run experiments that they say prove in-flight calls can be made -- and received -- safely. Something to do with installing low-power cell sites right on board the aircraft. These sites will then pick up on-board calls and send them directly to satellites.

So by 2006, the experts predict, I'll be able to phone my friend and say that I'm aboard an earlier flight than the one he'd planned to meet; tell my wife how close I came to missing the flight; finish the interview I started with a news source; and tell my children to phone me back when they finish the conversations they're having on their cell phones.

That's the good news. The bad news is that you will be able to do all these things as well, driving me, your fellow passenger, to distraction with your too-loud half-conversations about things that do not interest me but that I cannot avoid hearing.

I'm on airplanes a couple of times a week, most weeks, and I can't tell you how glad I am when they close the door before takeoff. That means the chatter of a dozen cell phone users will be hushed at least until we're back on the ground. For technological reasons -- or maybe just because there have to be some rules -- you have to turn your cell phone off when the cabin door closes, and keep it off until the plane is taxiing to the gate.

Here's my nightmare. I'm in the middle seat on a cross-country flight when the occupants of seats A and C whip out their cell phones and yak all the way from Washington Dulles to LAX. They'll have to yak loudly, of course, to be heard over the roar of the jet engines. And there's nothing I can do about it.

In a restaurant, I could ask to be reseated -- or leave. On a train, I could either ask to be seated in the "quiet car," where cell phone conversations are banned, or, if that refuge isn't available, I could wander off to the dining car. But on a plane, there's no respite from the compulsive cell user.

Worse, when the technology becomes available, won't its use also become mandatory? It doesn't matter if the airborne sales rep would rather read a book or solve a crossword puzzle. If the head of marketing wants to talk, the sales rep will talk.

And, if the conversation is extended and I happen to be seated nearby, I'll have a miserable flight.

I'm not, I hope, just being cranky. There was a cute piece in The Post last week about the tricks air travelers have used to avoid unwanted conversation with talkative seatmates: earphones that aren't attached to anything, even surgical masks suggesting that the wearer may have something communicable.

I thought the whole thing suggested a sort of I-don't-want-to-be-bothered snobbery. Don't most of us have sufficient social skills either to tolerate a few minutes' chatter with a stranger or to beg off (graciously, of course) on account of something we're trying to finish?

My complaint isn't that I can't stand talking to my in-flight neighbor. It's that I don't want to be a captive, unwilling eavesdropper on his personal or business conversations.

And I don't see how I'm going to be able to avoid it. Some stories have suggested that the airlines may impose limits -- say five minutes -- on airborne calls. Is that five minutes per call? But even if it's five minutes total, who'll monitor it? Surely not the harassed and overworked flight attendants. Am I supposed to hit my call button, summon the attendant and report the guy sitting next to me? All I can think of is the time I flew to Los Angeles seated next to a 6-foot-8, 365-pound pro wrestler named Big John Studd.

My only other hope is to think of those credit-card-operated phones they still have on some airplanes. Those apparently are so expensive they seldom get used except for real emergencies. The early talk is that the new technology will run something like two bucks a call in addition to what your cell phone company charges you.

But times have changed. There are people now who will jabber from one coast to the other just to prove to you they can afford to do it.

Is there no way out?