I saw them too. They were definitely aircraft coming from North America - probably to the same destination in Europe.
They will have been at different heights - assuming ATC is doing its job - but you can't see that easily from the ground.
I think these days the pilots tend to load up the plane's computer with its complete route, sit back and watch it do its job. They rely on GPS rather than VOR, but I expect old habits die hard, and the routes probably haven't changed since GPS was invented. A VOR station is still a convenient way point.
I used to watch them when I was at work as I waited for the train at Bebington station (there was often plenty of time for watching!). On a cold clear morning, you can see dozens in the sky at once.
One of the other things I used to see regularly at this time of year is the International Space Station. You can see it at either dawn or dusk if its flying over the southern part of the UK. NASA publish information as to when its visible here
http://spotthestation.nasa.gov/ It pops into visibility as it emerges from the earths shadow and disappears as it goes back in. NASA's timings are accurate to the second. You can set your watch to it. (Sadly not true of the trains!)
On one occasion I saw it and a smaller star - the shuttle - sail majestically across the sky. One of the other would be passengers asked me if I knew what it was, and word got passed down the platform and everyone waiting was looking at it and pointing it out. Its well worth looking out for.
