That's a fair point Dan - but the Euro LCC's don't do connecting flights. They specifically say that if you don't leave at least 2 hours between any connection with the same carrier and you miss your flight - well tough
The Airbus will modify its cruise speed depending upon the prevailing winds (don't know about the Boing). So if you've got a 100 knot tailwind the aircraft will reduce to .76 to save fuel and take advantage of the high ground speed. If its a headwind it will increase speed to .79 (max I think) as it's more economical (because you will spend less time in it....). It's also more economical to descend at a slower speed as you will commence descent earlier hence spending less time at cruise power....... We're only talking about perhaps a 40-60kg saving but x 1000/day = $$$$$$$$
Flying at 0.82 on a 2.5 hour sector would probably gain 3-4 minutes but I reckon would burn 300-400kgs of gas (roughly speaking about $300-400 worth). With LCC's working on very small margins it doesn't seem worth it.
A4