This question already has an answer here:
I have been trawling flight booking sites (expedia, skyscanner) for flights from UK mainland to USA in March/April next year. After many hours it is apparent that the less you pay, the longer the journey time and more connections you make. This seems crazy as you seem to end up doing MORE flying for LESS money. I am aware that there are subsidies and inter-airline and airport deals having arcane affects. Anyway, the best compromise between flying hours, number of connections and price is a journey starting in Glasgow, changing at Heathrow and terminating at Denver. I would prefer to travel directly from heathrow and cut out the other flight from Glasgow, but looking at the same return flight just from Heathrow to Denver DOUBLES the cost. Hence my question, if I book Glasgow to Heathrow to Denver, can I miss the Glasgow flight and turn up at Heathrow, check my luggage and catch the single flight to Denver and coming home, will I be able to get off at Heathrow and claim my bags without them transferring to the other flight to Glasgow?