A certain large 737 Texas headquarterd airline is implementing slower climb and much slower descent speeds than in the past.....sometimes doing a 260kt descent. Their flight ops is saying it adds just a minute or two to a 500 mile flight yet saves a lot of gas. It's driving controllers and the pilots crazy though. One pilot there told me he flies the 260kt descent till he gets close to the SID crossing with a mandated 280kt speed, speeds up to comply, then slows back down to 260 again after crossing! LOL.