The major airlines struggling with bankruptcy — United, Delta and Northwest — still don’t get it. They just don’t understand how to make money in the current airline world. And why not? Because they don’t know what the public wants. Sometimes I think they don’t care.

Only last week, while speaking with airline folk about Southwest Airlines, I heard that familiar refrain once again, “Southwest is not a real airline. They don’t face the complexities that we do.”

It was enough to make my head spin. Southwest is probably the only real airline out there — if you define “airline” as a business that actually provides a service and makes a consistent profit. No other airline in the air today can boast the string of money-making quarters and steady expansion that Southwest has posted.

Here is how I see it for the airlines. The rule is: Keep It Simple, Stupid — the KISS principle. The majors can’t get out of their own way. They love complexity. They are truly enamored of it; in fact, the more complex the better. But experience teaches the opposite: The more complex the operation, the faster an airline emerging from bankruptcy will fail.

Let’s call these Charlie’s Commandments:

1. Thou shalt not fly more than three types of aircraft.

2. Thou shalt not have more than two classes of service.

3. Thou shalt make airfares transparent, understandable and simple.

4. Thou shalt give passengers more than they expect.

5. Thou shalt make changing and refunding tickets simple.

6. Management shall treat workers as they want to be treated themselves.

7. Thou shalt honor thy pension commitments.

8. Management shall not pay themselves bonuses before they pay bonuses to their workers.

9. Thou shalt maintain a clear corporate image.

10. Thou shalt plan for the future realistically.

When I read in the newspapers that United Airlines is moving full speed ahead backward — to a United very similar to the one that entered bankruptcy almost three years ago — I cringed.

United’s executives are braying that they know what flyers want: more services, more choices, more luxury. But United’s passengers have been voting with their wallets for years, telling the hapless executives that this is not true.

Delta Air Lines has gotten its management equation, operational complexity and balance sheets so messed up with the Song fiasco that it can’t even really begin making plans for the future until it undoes the past. And Northwest Airlines is saddled with those old, fuel-thirsty aircraft –true, those planes allowed the company to survive over the past five years, but thanks to today’s high fuel costs, they now threaten to bleed the airline dry.

What else do these three airlines have in common? They all have abysmal management/worker relationships. Northwest and Delta’s pilots and flight attendants are all threatening to strike. United’s workers are still reeling from the realization that its management stripped them of their pensions while at the same time finagling a stock bonus for themselves from the “new” United Airlines that emerges from bankruptcy.

It seems too late for these dinosaurs. They seem doomed to repeat their failures.

I assure these airline executives — and the complicit bankruptcy judges — that passengers want the airlines to follow the Ten Commandments written above. I also can promise them that the closer they stick to these commandments, the more profitable their airlines will be.

Simplify aircraft types. Simplify airline service. Simplify airfares. Simplify refund policies. Make your customer’s life as easy as possible. Treat your workers right. Plan ahead realistically.

Business doesn’t get much simpler.