From the comments on this post: there’s a vigorous debate going on about whether some form of congestion would really reduce delays, given that flight schedules (for business travelers at rush or for international flights connecting to overseas hub banks at planned times) are not easily adjusted. But there’s another point I want to bring up: the airline lobby has decried the FAA’s proposed regulation, arguing that congestion pricing “does nothing to fix the primary cause of delays – our nation’s increasingly antiquated air traffic control system.” Molly Feltner at SmarterTravel.com editorializes further: “The government is basically buying time so it can delay the daunting and hugely expensive task of implementing a new air traffic control system.”
Both responses to the regulation proposal are disingenuous. We all know that thanks to the FAA’s incompetence/underfunding/”rebenchmarking” (or whatever else you think of the FAA), the full implementation of the NextGen slate of technologies is years off. (Not that NextGen will be panacea, but it will help.) Neither the ATA for Feltner acknowledge what we’re going to do in the mean time–between now and not yet. Demand for air travel continues to increase, and we want to avoid summer delays like we saw this year. There has got to be an interim strategy. If you think congestion pricing isn’t the answer, you need to offer viable alternatives. We’re waiting.
Evan Sparks's Aviation Policy Blog 
So just guessing, but would congestion pricing mean higher prices at peak times? If so, don’t we already have that? When I try to book a flight, it’s always cheaper to go at odd times — whether “odd time” is defined as day of the week or time of day or, sometimes more dramatically, time of year. It can be hundreds of dollars difference, even on a 45-minute flight, if you pick a different day or time of day other than “rush hour.” (Or even a different airport, such as going to Milwaukee rather than Chicago’s O’Hare.)
If that’s not what congestion pricing is, I apologize for my ignorance and ask you to elucidate.
As for reducing delays—I can see how it might reduce overbooking, but I don’t see how a change in pricing would change delays, which are usually caused by problems such as mechanical issues, bad weather, or staff not available. Delays aren’t caused by the number of passengers during peak periods—especially now that airlines have the policy of your being at the gate 20 minutes prior to flight time or you lose your seat (on overbooked flights anyway). Most of the delays I’ve experienced has been because of something other than the plane being full.
Of course another cause of delays is that every airline at any given airport seems to be schedules for a take-off time within two minutes of every other airline. In these cases, delays are caused because a gate is not available or 15 planes are in line for take-off. If one plane is a little late, everyone is thrown off. If they just said, “hey, only one airline leaves at 10, if you want to be on that plane, make your reservation months in advance or take the 10:15 flight,” rather than having flights scheduled at 10, 10:01, 10:02, and so on, one plane being a little late wouldn’t throw everything off so badly. It might mean you have to take a flight late at night or earlier in the morning or mid-day, but given the delays, that’s probably when you’re taking off anyway. (Though I must say that, with United out of O’Hare, other than during ice-storms, I’ve been very lucky with the timing of flights — very high percentage of on-time flights, or at most just brief delays.)
Waltzingaustralia, you’re right that ticket prices already vary by day and time-of-day, but that variation is (largely) due to differences in demand for flying. If more people want to take a 8am flight than the 6am and 10am alternatives, the airlines are going to charge extra for the preferred time. More demand = higher prices. But these differences in price don’t reflect the cost of congestion, even though they seem to fit the same pattern. The airlines will adjust their prices based on demand because it’s in their own interest to do so; however, with congestion each airline’s choice (of when to fly) imposes a cost on the other airlines: one more of my planes makes it harder for you to operate yours efficiently. Congestion pricing is meant to force airlines to pay the cost of their actions (a cost they would otherwise ignore). To answer your question, congestion pricing would (or at least should) mean higher ticket prices at peak times, above and beyond the current differences due to demand.
Regarding your second point, I think your last paragraph answers the question you raise in the one above it. Higher prices –> fewer tickets purchased –> fewer flight scheduled –> more ‘slack’ in airport schedules –> fewer problems when one thing goes wrong (no more cascading effect of one small delay). At least in theory.
I didn’t think airlines got to schedule their own flights. I thought the times were handed to them by the FAA. So it wouldn’t be fair to penalize airlines for taking off at the time the FAA said they were scheduled. (I know all airlines want to take off at the same peak times, but they don’t get to create the actual schedules — those all have to be cleared through someone else.)
And to whom would the airlines pay the cost — the government? I can’t say that I’m fond of the idea of any program that pays penalties to the government — costs which are then in turn passed along to the customer. Why not create a system where incentives are offered to people and corporations to take different flight times (such as, for example, airlines that also own hotel chains could offer a free night at the destination for people willing to fly in the night before, or maybe a rental car discount, or an upgrade — those are always popular). Do something that doesn’t hurt the airline, doesn’t hurt the customer, and doesn’t give more power and money to the government.
WaltzingAustralia: When I try to book a flight, it’s always cheaper to go at odd times
There are multiple reasons for this – none have to do with the airport, which charges a standard amount regardless of time of day.
Airlines have hundres of fares, and they change constantly during the day. Some airlines, such as Ryanair, have taken pricing to the level of a competitive advantage, trying to both fly with every seat full (drop the price as low as required to do this), as well as to maximize revenue (charge no less than what is required).
First and foremost is supply and demand… If the plane lands at 8:00am and is the ideal flight for business travellers, then the minimum price for the flight will be high, and there won’t be many of them on the flight. Why? Because the airline can sell all the seats at a high price, so why would they offer any at a lower price? [It’s never as balck&white as that, but that is a strong trend.] So you’ll see only higher prices because there are few/no seats with lower prices.
Secondly, on a flight with a high demand for seats, not only will there be few seats with a lower price, but there’s lots more folks trying to buy them… so you are likely to have been beaten out by someone else. And unlike what happens when the apples at the supermarket get sold out, the airlines don’t just make more seats available at the lower price (put more apples on the shelf). Rather, they’re happy to offer you the seat at a higher price — and the historical data will strongly indicate the number of seats they can sell at each price, by hour, by date, by day of week, by route. So there may have been a few seats at a lower price on that highly desirable flight time – but the high demand has resulted in someone else buying them already.
But it isn’t because the airport charged the airline more money for that departure slot.
My thoughts: During extreme-demand times, charge more for both arrival and departure slots (I pick my flights both because I need to be somewhere at a certain time, not solely because I want to leave somewhere at a certain time), and require certain minimum sizes of aircraft (why land a 19-seater when you can land a 737? Or a 777?)
Waltzing: the charges are not to be paid to the government (well, except to the extent that most airports are publicly owned). They would be paid to the airport. Right now, congestion charging for airport slots is verboten, so even though a rush-hour slot is more valuable, it costs the same as a 4 am slot. The FAA’s proposal would allow airports to incorporate congestion weighting into their charges. Revenue would still go to airports, but airports could use the pricing to minimize crippling delays and rationalize flight schedules.