Hi there, I'm "crowded." Fly me very carefully.

The latest in airline advertising? No, but the prudent passenger might profit by operating as if it were. It looks as if the air traffic jam that stacked up the skies this summer will continue a while longer, and swelling complaint files indicate that not everyone is altogether straight on how to cope.

It's not that somebody up there suddenly hates you. It's just that the big, new low-fare explosion confused an already-confused situation. You could lie down until it all goes away, but if you're partial to trouble-free travel, now and at the peak-peak-holiday periods to come, there's a better idea: Study the current crop of the horrible examples and take appropriate precautions. The following, for instance, offers object lessons:

NOW YOU SEE IT, NOW YOU DON'T - Everybody loves a low fare and a recent pair of New Orleans-bound passengers were no exception. When they telephoned, though, they discovered that not only were all the low-fare seats sold out for the day they wanted but for the following four days as well. They took the news as gracefully as possible and signed up for full-fare tickets.

The result might still have been a happy holiday but for one further development. At the airport, they ran into friends who did have cheap seats, having bought them two days after the first couple had been told there weren't any.

Dirty doings at the crossroads? Not at all. Things do change. Most likely there was a cancellation, and the second couple called at just the right moment. It's the same sort of occurrence that drives travel agents to drink, as in the case of the customer who phones to say, "What do you mean there were no seats? I just called the airline directly and got some."

There's no guarantee that fortune will smile on those who dial and re-dial (and sometimes you'll find the lines impossibly busy), but if you're seriously interested in saying, that could be what it takes. The first move, though, is to ask the airline reservations clerk about a "wait list." With a little bit of luck, they'll then call you if a cancellation comes through. At the same time, don't entirely dismiss the idea of calling back. An extra push has been know to pay.

NOT-SO-FUNNY THINGS THAT CAN HAPPEN ON THE WAY TO THE AIRCRAFT - They could be known as Mr. and Mrs. Meticulous, and naturally they got themselves to the airport an hour ahead of flight time as instructed. The only thing is that several large groups and assorted other passengers arrived even earlier and due to the substitution of a smaller plane, there were not enough seats to go around. Mr. and Mrs. M. got a cursory apology but no transportation. Since the aircraft change meant those rules for "denied boarding compensation" didn't apply, there was neither free ticket nor soothing check to say "so sorry."

In boom times such upsets happen, and just as early birds get the worms, early-bird passengers get the seats.

For similar reasons, write off the idea of getting a confirmed reservation by phone and then waiting until you get to the airport to buy your tickets. You could still be standing in a nice long line while your plane takes off without you. At some peak periods you can find service representatives to help you jump the line, but don't count on it.

NOW PLAYING: THAT GRAND OLD FAVORITE, "HURRY UP AND WAIT" - Because he commands it, the world normally works perfectly for a titled Englishman who commutes across the Atlantic. He therefore turns a fiery red when he tells of a recent trip via Concorde. It took precisely half again the time of the whole air trip to deliver the passengers' luggage. He can't believe it happened to him, but lesser folk have noticed the same sort of development all over the place, which may account for the fact the even when there's not a crunch, more and more travelers are flying with carry-on baggage only. U-Haul is a pain, but foregoing the wait, wait, wait at the baggage carousel is pure pleasure.

YOU WILL NOT PLAY BY THE RULES - It was a nice, neat tour package, so they bought it, Super Apex fare and all. But apparently it was not appreciated by quite enough other people, so the tour operator canceled out. The would-have-been tourtakers got their money back, of course, though not quite all of it. In this case, the airline claimed $50 due to the fact that that's how the rules read. Remember: changes or cancellations cost, no fooling around.

Can this happen in the United States of America? Sure enough. Many of the new low fares differ from the old low fares in that they permanently commit you to one flight, one airline, or else. Thus, if the flight you're booked on is late but another one is ready to move, it's just too bad because these days switching most low-fare tickets would be exceedingly expensive. Today anyone who subscribes to "better safe than sorry" must look long and hard at everything that comes with the cheap ticket.

Even then, there are occasional nuances only a truly devious mind can grasp. Actually, this season's likeliest prizewinner in that department was recently revealed in a complaint to the Civil Aeronautics Board from some Philippine Air Lines passengers. Involved were 30-day round-trip cheap tickets, but the return portion could be booked only in the Philippines seven days before the desired flight. Oddly enough, no seats were available seven days before the allotted 30 days were up, so the passengers had to pay full fare to get home.

Of course, you could say that this sort of thing does make for a memorable trip. But it would be hard to smile at the same time.