Snoonbill and Flybywyre - what are you talking about. Luton has excellent road connections and has a rail link. Admittedly there is a 5 minute journey by shuttle bus to complete the trip from the new airport station to the terminal but then there is a 5 minute walk from the Heathrow Express and Underground to get to some of Heathrow’s terminals.
If you want to catch a train between 18:00 and 19:00 to London then Heathrow will provide 4, Stansted has 2 as they are now operating an off peak service while Luton has 9 calling at 6 central London stations. Luton also has a 4 train an hour service to Gatwick and the south coast plus a direct rail link to Nottingham and the Midlands.