I'll put on my tinfoil hat and asbestos underwear and wait until I get a reasonable answere to these two questions.

BUMP!

BIG Question:

I understand that the terrorists turned off the transponders..... Why do civilian aircraft transponders have the capability of being turned off....thus allowing the aircraft to fly without the FAA having the ability to track altitude?

Airlines do not trade passengers to fill one flight instead of letting 3 1/3 full flights take off within 30 minutes of eachother. I have flown on 15 round trips since 5 feb 01 and have never had a flight cxl'd due to not having enough passengers. They figure out real quick whether or not enough passengers fly during those hours and whether or not it is profitable for the airlines to conduct those flights. You have to remember, when the flight gets to the west coast it probably turns around, hits Vegas and another city or sometimes 2 before it gets back to the east coast. In other cases the flight begins in LA flys straight to NY and then stops in 1-2-3 places before it gets back to LA when it starts all over again. This is how they make up for only flyig 50+ folks one way, non-stop. Look at daily operating costs not individual flights. Just my two cents.

Empty flights happen all the time but it's less frequent now than in the past. Tuesdays are one of the better days to fly because it's a light day. Sundays, Mondays and Fridays are the heaviest. Most one or two day meetings tend to be scheduled early in the week which forces you to fly Sunday or Monday. If it's a longer time it tends to wrap up on Thursday or Friday.

In the end, I expect the FBI to announce that, after a thorough examination, they find that Tim McVeigh acted alone in piloting four aircraft that struck buildings in New York and Washington.....

Sigh.

Not to speculate too much but a low passenger count would be advantageous to the terrorists in controlling the aircraft...in that a full load might include some hero types who might try to storm the cockpit. They certainly didn't want the planes going down someplace like the one in Pa.

"Why do civilian aircraft transponders have the capability of being turned off"

Couple of reasons: 1. Transponders can give erroneous results. If so, they are turned off. Bad autonomous informtion is worse than no autonomous information. 2. Transponders are turned off (actually, placed in 'standby') on the ground to reduce traffice control clutter. Can you imagine trying to track an aircraft taking off or landing at a busy airport like LAX or JFK if every aircraft at the terminals or on the taxiways had their transponder on? The traffic controllers scope would be unintelligible.

I've taken a lot of coast-to-coast flights for business. When the economy is good, people love the morning flights to get to their destinations early and get a good night's rest before starting the next day.

When the economy heads south, the morning flights tend to see the popularity drop like a rock. People who take the evening flight can not only get in a day worth of work when they leave, but they can go to work immediately after arrival.

The other thing to remember is that even when flights run nearly empty, there is big business in hauling freight, everything from mail to machine parts. The freight business is the steady part of the airline's income. They can break-even or even make a small profit on a nearly-empty passenger flight if they have a full cargo hold.

Big freight-only carriers such as Emery, FedEx and UPS know this and will keep their own planes in the hangars when capacity is available from the commercial airlines.

When it comes to freight handling, most urgent cargo likes the morning flights-- because the sorting for the end-destination at the arrival terminal generally takes place during the night. Cargo which arrives in the morning will queue for sorting and usually will be to late to get on the trucks making their rounds for the day.

He's probably getting at what I was getting at when
I asked similarly, why only 266 passengers among four
planes?

Collusion. Transponders turned off - why? NOT ONE sent
the four digit code - were the pilots or a co-pilot in
involved or one prevented the other from sending it or
secretly turned the transponder off?

Look for a Third Position fascist group with rich and
respectable connections, in some cases elected or other
officials in this network, incl. a notion of reviving
real authrentic to antiquity paganism as the only faith
appropriate to a white man, as the local collusion part.

Some dubious but sometimes correct people in Europe,
according to a Usenet post, are thinking it involves
American collusion.

I don't have any theories, but I did take note that the flights seemed relatively empty. Not just one of them either. Yes, this would be more helpful in terms of passenger control, but if this was planned for "years" in advance and they needed people on the ground etc. etc., I wonder how they could have managed to board multiple empty flights simultaneously. No tin foil hat for me. I simply wonder if this shows how well managed the operation was on a logistical basis, suggesting there had to be help inside the airline?

2. Transponders are turned off (actually, placed in 'standby') on the ground to reduce traffice control clutter. Can you imagine trying to track an aircraft taking off or landing at a busy airport like LAX or JFK if every aircraft at the terminals or on the taxiways had their transponder on? The traffic controllers scope would be unintelligible.

I can understand this...but an auto-shutdown could be designed the craft is on a tarmac.... to avoid the added scope clutter.

In my limited experience (about 25 commercial flights in the last 30 years) I have never been on a flight that wasn't at least 75% booked. Most were packed!

I've never known airlines to work with each other to "fill" flights... sometimes they'll cancel one of their own to fill one of their own later on... sometimes.

Usually what happens is that the plane is needed at the other city so it can make return trips, so even if it's just 1 person, they might have no choice but to send it anyway. Or maybe the flight crew needs to get back, so they take it anyway.

Anyway, it does happen, and I've been on a few flights like that. It's actually really nice when that happens, compared to being crammed in like sardines. Nothing like having an entire 757 wide body to just yourself and a handful of other people. :)

Re-read point #1.

I guess that I am just saying....there is a technical solution...there must be one that will prevent a terrorist pilot from doing this again.

Nuke em Dano?

Several good, reasonable answeres in the first few replies. I'm not suggesting anything at all, but when I heard the numbers of passengers, it seemed very peculiar. It still does but not to such a degree as it did about 15 hours ago!