Get a ferry to Liverpool then a train www.nationalrail.co.uk. Google Liverpool to Northern Ireland ferries. There are several companies.
If you want to fly, fly to Manchester Airport. Then catch the direct train from the railway station inside Manchester Airport to Blackpool. They run every hour
You won't be able to get a flight. It will be easier for you to get a ferry from N.Ireland to England and drive to Blackpool or get the train.
You can try "Citywing"
they do Belfast to Blackpool via Isle of Man (Quite expensive though)
Now airport gone get a plane to Liverpool or Manchester then the train....
Twa t, Fly or ferry to Liverpool. then get a train. Are you utterly thick?
ask a travel agent.
