British Airways

Name for premium economy
World Traveler Plus

Aircraft type
B747-400 (both configurations)
B777-200
B767-300 (fleet gradually being fitted with Traveler Plus seats ("dusking") as well as "new" Club World flat seats)

Plain economy also exists on same a/c?
Yes, on all aircraft.

Seat improvements over economy (pitch, width, recline)
38" of pitch provides noticable difference compared to 31" in World Traveler (long-haul economy class). Seat width is extra 1" compared to economy at 18.5" with immovable armrests. Noticably (although slight) greater recline. Footrest forms part of the seat.

Food & drink improvements over economy
Not signifigant. Same food and beverage service as economy class, but WT+ passengers get served first and drinks are poured into real glasses. No welcome or take-off drink provided.

IFE improvements over economy
- Smaller and more intimate cabin with only five rows in the B747 and B777 (2x4x2 accross), and only four rows in the B767 (2x2x2 accross). Compare this to 3x4x3 in the B747 and B777, and 2x3x2 in the B767 in economy class.
- More comfortable seats with more space designed by Recaro, includes footrests.
- IFE system same as economy class except there is access to games beyond the standard 18 channels (not AVOD anywhere on aircraft).
- Generally a quiter and more relaxing cabin, with no access by regular economy passengers permitted.
- Laptop power points/Empower (adaptor required).
- All paid fair classes (W,T) are upgradable to Club World, generally considered the best use of miles on BA when combined with a relatively cheap Traveler Plus fare (that will earn points and miles).

Baggage allowance
Hold luggage: same as economy class
Cabin luggage: two pieces weighing no more than 12kg/26lbs (compared to one piece in economy at 6kg/13lbs)

On the ground (check in, lounge access, priority boarding)
Nothing extra at homebases of LGW and LHR. Curiously, there are sometimes dedicated Traveler Plus desks at stations elsewhere (i.e. SFO, LAX) that sometimes also double as check-in desks for passengers who checked-in online and only need to drop off hold luggage.

Enhanced mileage earning?
Extra tier points (earned towards status): 75 instead of 60.
25% bonus on actual miles flown.

Website
British Airways WT+ Info
Picture of World Traveler Plus cabin aboard B747-400
Picture of twin seats by window aboard B747-400