Oh god, I thouh we were over this!
They both have their advantages, but MAC, you have to admit it sometimes. (You know what im saying)
1.) UAL has a large A32X fleet, something which the A330 can take advantage of with it's CCQ capabilities.
UAL has an even larger 757/767/777 fleet, which the 767 benefit's from these aircraft through commonality.
2.) The A333 can haul -more- cargo than the 767-400.
MAC, this has been stated over and over, US airlines do not have such a need for cargo as smaller national carriers do, therefore the 767 provides sufficient cargo space, especially for the trans-con market.
3.) The PW4000 engines already hung on the US A330's make for ease of maintenance with UAL's huge PW4000 'fleet'.
All 767 series aircraft are available with the P+W4000 series engine. (Come on, that was a bad one

)
Also, heres one for the 767, it is more suitable for the demanding trans-con market, since it is a lighter, more flexible aircraft.
Why is it the 767-400 is having such a difficult time?
Could it be there is a somewhat puzzling picture Boeing has created in recent years too?
Some of the decisions it's made in recent years, from it's tardy reply to the A320, the attack mode on/off flip-flop on viability of a VLA, the move of the Seattle headquarters, shifting of narrowbody 757 production to Wichita, layoffs numbering over 40K, outsourcing the 747X wings to Japan (and torquing off Boeing employees at home) to now a potential -changing of mind- on 747X to begin with..and possibly shifting effort to building a new generation of 250 seaters (which would be a neat thing to see I might add).
Has you head begun to spin yet? Mine has.
Seriously though it points to a slightly confused operating picture. It's no wonder some airlines could very well be waiting Boeing out before commiting to a large purchase of jets like the 764 due to issues with the airplane itself, but maybe more importantly, the company making it.
Just my candid views and opinions, twinged with a taste and sincere yearning for that wonderful word called -fact-. Oh where oh where is it?
A very biased, close minded view I might add. How in on earth is that related to the 764s "problems" (Which really don't exist if you think about it). "Airlines waiting Boeing out before commiting to a large purchase of jets like the 764 due to issues with the airplane ifself"-what is this a big game or something? MAC, mabye if you knew more about this wonderful airplane, and opened your mind you would really understand.
-Tom