Don't get me started on trains, however I have become very expert at fare splitting which has saved me countless pounds in recent months. That is something that is not so easy with plane tickets unfortunately.
I used to do that too, especially Midlands to MK, then a travel card from there with a Network Railcard. Usually saved about £5 directly off the fare, and the tube was thrown in for free - as long as you stopped at MKC in each direction, AND you were coming back same day, it was worth doing - but always needed asking manually at the cash desk, machines no use.
I stopped doing it as more advance tickets became available, now I have a national Railcard, so it is rarely worth the bother.
As for flights, it is more a case of splitting fare and carrier, there are various combinations which work, not always with locos, but often taking advantage of cheaper APD by not flying a lh sector from the UK.