At all cost, avoid an airline named Ryanair. It is by far the worst airline on earth. If there are airlines on other planets this would still be the worst. Ryanair was initially used for the transport of cattle, but then the animals refused to be serviced by Ryanair. The airline is so bad that safety instructions are posted in front of every seat to alert you that crashes are quite frequent on Ryanair: emergency landing instructions are Ryanair's idea of flight entertainment. They also put a life-vest over every passenger's head because in one out of two flights you will need it. Wait: but they have "Priority Seating" which only means that you get to stand at the gate like everyone else but "Priority Seating" people get to stand against the wall (but not shot, thankfully). Also, they don't believe that airplane seats need to recline. Oh, and Ryanair doesn't use Heathrow London Airport: they use Luton airport which is far worse than Beirut Airport in 1938 (and is one hour and a half by car from downtown London).
PS Wait. Ryanair has an application for mobile devices and if you check-in using the device they make you leave the check-in counter and go to the kiosk ( they don't believe in office) and buy a boarding pass. So the mobile check-in is meaningless.
PPS oh, and how do you know that the lavoratory on the plane is occupied? The stench gives it away.