In the very early days of Air Wales I researched operating Shoreham to Cardiff, the Do228 did a demo flight and we had a well attended open day. Many laughed at the idea but we had a guaranteed usage of seats from Legal and General and from Ford Motor Company that would have given close to a break even on each flight. We also had the Let410 into Pembrey for a demonstration. I was only the MD, unfortunately the owner didn't share my enthusiasm as was his right.
This was more than 10 years ago when the economy was better, it wasn't easy starting an airline then but it is even harder now so these guys will have a mountain to climb if they are serious about it.
I certainly wouldn't write it off but I would hope they have done a LOT of research into what market is available and sought some guarantees if possible.
Over many years I have been presented with a lot of start up business plans and it is nearly always the ones that start with a glossy brochure flying x aircraft between Y&Z with details of the crew's socks and the CC's hat that fail to get going.
The ones that start with 'We have identified the need for....' and then fit the equipment to the need stand the most chance of making it.
Good luck to them but please guys do the boring bits and the bean counting first.