I would agree that Air Sylhet are naughty.
They don't have their own AOC or OL however once you talk to them about this directly they do admit that they don't have their OWN AOC or OL.
Unfortunately this comes under hoax. The people they are targetting for investment is mainly the Bengali community who have a very low literacy rate, therefore by saying "...confirms UK Air Operating Certificate (AOC) and Operating Licence (OL)" what they are really doing is misleading vulnerable people into believeing they have their own license therefore they are legal and this itself reassures potential investors to invest.
They are actually abusing and taking full advantage of the vulnerable people who have a low literacy rate into investing in their company.
The funny thing is that I don't think the law can do anything to stop them.
