There is nothing wrong with ZB
's current fleet of 757s, and I can't see them replacing them any time soon.
The 757 is a useful tool for ZB
because it is ideal for some of the more longer short-haul charter routes that ZB
and others operate on like the Canaries, Greek Islands, Egypt, The Gambia, Cyprus and Turkey as well as Gibraltar with it's restrictions. They have the A321 which although more or less matches the 757 in terms of bums on seats (despite ZB
's configs), is pants on some of the routes ZB
send 757s on, and also the A321s are ideal for the Scheduled routes so why change that now?
Besides the A321 the only aircraft that ZB
could possibly replace the 757 with is the 737-900ER, but that wouldn't appeal to ZB
because they don't have any 737s in the fleet and I'm sure that there may be one or two payload issues with the 737-900ER vs 757-200 on some routes.
Gkirk is right, there is nothing out there at the minute that the charter airlines can replace the 757 with unless they are hellbent on simplifying their fleets and are prepared to axe routes/impose payload restrictions on routes to do this.
Age shouldn't really be an issue at the end of the day (unless you are one of the stereotypical types that ZB
fly every year on their annual jolly to Benidorm/Majorca/Costa del Sol and would probably baulk at the aircraft age if anybody told them), and as long as they are properly maintained there is no reason why ZB
have to replace the 757 very soon because they are old.