Guv
Here's the cabin air link
http://www.boeing.com/commercial/cabinair/ecs.pdf
You (or(Delta) do modern types a great diservice by casting aspersions on their reliablity. Or maybe Delta just don't treat em right.
My company operate 767s and it's little sister 24 hours per day and have few technical problems.
For the last few years they have carried tens of thousands of pilgrims to Mecca with 4, 8 and 12 hour sectors with a better dispatch rate than any other operator or type on this massive operation. (including Tristars)
This is in no small part due to the aircraft being maintained to the highest standards by some of the best engineers in the business.
And in no small part to it being a very reliable aeroplane.
I don't doubt that this applies to any commercial jetliner as if this was not the case, the manufacturer would soon find very few customers beating a path to their door.
The point is that a trijet has a high fuel consumption and fuel prices are very volatile. A middle east war could put you out of business overnight.
A "previously enjoyed" A310 would do the same job for not much more capital and a greatly reduce fuel burn. And if you get an old enough model, you could even have an engineer!
