Difference between E and T booking classes?
 

Hopefully this is ON-topic.

I'm just booking a a WT+/WTP flight from LHR - NYC. I can book into either E or T, depending on the price I want to pay, but the conditions for both are the same (£100 change fee, non-refundable, but upgradable for £100 + difference in fare).

Apart from the price difference (£700 for T vs. £1400 for E) are there any other differences (ability to upgrade at MMB perhaps?) or is it just flexible pricing based on ticket availability?

Many thanks.

In that instance T will sell out first forcing customers to buy E.

On other routes, or from different point of sale there may be a whole raft of differences