Flexibility rules might differ.

And availability. Presumably one buys the lowest fare which accomplishes the purposes of the planned trip and which is available at the time.

It's entirely possible that at walk-up or close to, all that's available is Y and you either buy Y or you don't go. Y, of course, is a reason to overbook by one more.

IIRC, Y is fully refundable/changeable and B and M aren't.

Y also improves your upgrade chances, especially if you aren't Diamond. As a PM on a Y fare I will trump most diamonds for any BFUG's unless they are on a full Y fare as welel or using an SWU.

Often time B fares may be changeable for no fee and sometimes refundable.

When FCM Becomes Ridiculous
 

So, I went on .com to look at loads on a specific flight and this is what I saw:

Economy (M) - $384
First (P) - $354

Now, I'm not one to usually complain but I found this very odd and what is even more odd / irritating is that UGs have not been cleared on this flight yet DL is willing to sell an F seat for less than a Y seat. I get the desire to sell seats in F but for LESS than coach?!?

GRRRRRRRRR....:mad:

Are P fares flexible or refundable? (I'm asking because I don't know). I mean, AA sells "Instant Upgrade Fares", which I used for my honeymoon next year, and the "Instant Upgrade Fare" was far less than the Flexible Economy fare. But the catch is the Instant Upgrade Fare I purchased is non-refundable.

P fares generally have a change fee associated with them, and are not refundable.

The M fare is almost always not refundable and has change penalties as well. OP wasn't complaining about a flexible Y fare which would cost a lot more. This is an M fare, which while expensive, is more than the first class fare and almost certainly has the same restrictions.

Stuff like this is what ticks frequent fliers off. DL not upgrading elites and selling the seats for less than the coach fare.

Any M fares that I've purchased within the last year have been refundable, with no change penalties or refund penalties. I've changed and cancelled plenty of them thus far - so I am sure. :)

Again, that is just my experience.

A business making money is irritating?

Agreed, although UA and AA are engaged in the same game now. It's the new world order of airline yield management.

I would agree - in this case, I would venture a guess that the P fare is non-refundable, and the M fare refundable (you can determine this by reading the fare rules for the class you select on the next screen in the booking process.)

If my assumptions are correct - the premium they are selling in this instance is flexibility to change your flights without penalty.

Depends on the route of course... all of my flight routing has fares where refundable starts at B and is sometimes only Y.

That makes sense! I have on more than one occasion found a fully refundable H fare from BDL-SNA (stop in ATL) so yes, route specific.

I have experienced this year on a few routes where the P fare is cheaper than coach. I've seen P almost the sam price as LUTKQ fares, let alone BMY.

One thing to keep in mind is most travelers probably don't search for BMY fares, most are probably looking at the cheapest fares. That is unless BMY is all that shows up.

A business throwing away money (do you think it would sell any fewer P fares if it raised them to the same as the M fare? Or even $20 over?) to the detriment of its supposedly-best customers is irritating to those customers, yes.