Flying

Are air fares based on the cheapest "back of the plane" seats?

No. Air fares fluctuate from the time they are first posted until the last minute. Generally there is a First Class fare which cost the most and has more space and services, a business class and an economy class. The latter has the least amount of space and services Buying a ticket in economy class at the last minute could cost as much as a business class seat.

, can seats be upgraded for the longer flights?

Most airlines have upgrades that you can pay for up to the time before boarding. But it is not guaranteed to be available or inexpensive.

If you are talking about advertised prices, yes, they are usually for the cheaper seats. There will always be other seats that are more comfortable at a higher cost.

We fly Delta a lot and Delta has pricing with of course, First Class as the most expensive, then Economy Plus (slightly more room than Main Cabin), then Main Cabin (Economy), and cheapest (forgot the name).

The cheapest seats (not Main Cabin) don't allow you to pick your seat preference so you are more likely to wind up with seats at the rear of the aircraft or in middle seats.

You need to tell people what airline you’re looking at etc. For example an earlier poster talked about Delta Delta offers a basic economy fare. The basic economy fare not let you upgrade to a better seat. You may be able to pay to pick a seat, but it will be an economy seat. If you don’t pay or it doesn’t give you that option you may be in the middle seat in the back.

Delta’s economy or main cabin fare does let you pick a seat and may or may not offer you an upgrade to a better cabin or better seat. It just depends on how they are selling. Within the economy cabin Delta also has their comfort plus. Basically this is just a seat in economy with a little more legroom. You may be offered the opportunity to upgrade to it.

For international Delta also offers premium economy and business or D1. Sometimes you may get an offer to upgrade to those sometimes you may not. There’s a myth out there that there’s always going to be a cheap offer and it is just that, a myth. I’m flying to and from London Next month on Delta. On my flight to London, there are exactly 2 D1 tickets left. (and that’s from expert flyer not from counting the seat map ) so I would expect its unlikely than anyone’s going to get a cheap upgrade. My flight back is in their premium economy cabin. The cheapest upgrade I have been offered for a business class seat has been $1500 ( I passed)

But the truth is that every airline has a pricing system somewhat like this so you need to know what airline you’re looking at and then look at their rules, cabins etc. if you let people know which airline you’re looking at, they can probably give you better guidance on what your options might be.

Avoid the seats adjacent to the toilets. Whew!

Within the economy cabin Delta also has their comfort plus. Basically this is just a seat in economy with a little more legroom.

Also free booze and “deluxe” snacks, domestically anyway. All Delta passengers get free booze transatlantic or transpacific, however. I don’t believe United or American offer free liquor in economy, beer and wine only are free.