JetRob
The Jet2 advert says Majorca From £19.99 All Fares are One Way incl Taxes.
Yes, the £19.99 fare is available. Take LBA-PMI 28th Aug, the base fare is £0.99 + £19 Tax = £19.99.
So NO it is not false advertising as the rules stand at the moment.
However, this is not the fare you will be charged. To this fare you have to add compulsory charges for a Booking Fee, Check-in Fee and Credit Card Fee. Additionally there may be other optional charges.
Again I say NO it is not false advertising ......... but only because they are not obliged to include All compulsory charges in their advert.
Incidentally, if you were to travel on the 28th Aug and return 1 week later, the return flight will cost you an extra £132.99 incl tax giving a return fare of £152.98 plus of course your Booking Fee, Check-in Fee and Credit Card Fee.
So the one-way fee of £19.99 suddenly does not look so attractive.
The advice is quite clear, look at the final total before booking.
I would also point out in fairness that Jet2 are no different in this respect to all other Lo-Cost airlines.