Liverpool's case isn't helped by its lack of a coherent public transport strategy.
Around 2008 and '09, the N86 linked the airport with the city centre late at night and early in the morning. I used LPL frequently during this time and the N86 was a lifeline. The morning bus was full of passengers and airport workers (cabin crew, retailers, ramp workers etc). It ran through the main student district, giving price sensitive students an affordable means to reach the airport for that first wave of pre 8am departures. National Express, Terrorvision, and the 500 Express also linked the airport to the city centre. The public transport links made the airport very accessible.
Fast forward to today. The N86 has gone, as has the National Express link. The Terrorvision links the airport with Manchester city centre but no longer commences/ends its journey in Liverpool. The 500 still runs, but only during the day when cheaper alternatives are available that are just as fast. If your flight departs before 8am, or arrives after 10pm, it is impossible to reach the airport using public transport. The only alternative is taxi (£15 to the city centre) or car.
The decline in public transport has been matched with an assault on motorists. This is not unique to LPL, but it does exacerbate their access problems. Post Glasgow terrorist attacks, motorists can no longer drop off in front of the terminal building. They are now directed to the short term car park. Anything more than a 5 minute stay attracts a £2 charge, increasing by £2 every 10 minutes. Long term parking costs £55 for three days. Black cabs are charged £1.50 to access the airport grounds. This is passed on to the customer. Private hire taxi's are reluctant to pick up because of the potential to rack up short term parking charges.
Motorists picking up/dropping off passengers attempted to avoid these charges by dropping off on the access road. The airport painted double red lines, installed hidden cameras and stared issuing £100 fines to motorists who stopped outside of the designated areas, even if just for a few seconds. The local press had a field day! Regardless of whether it was a right or wrong thing to do, this practice alienated a massive chunk of LPL's potential market (a 'la Ryanair).
I live in Liverpool city centre. I am relatively price sensitive when booking short haul flights. I often find that it is cheaper and more convenient to catch the train from Liverpool Lime Street to Manchester Airport than it is to access LPL early morning or late at night. The train to MAN costs £6 each way and only takes 25 minutes more than a taxi to LPL. personally, I find it ridiculous that MAN is easier to get to than LPL from Liverpool city centre! If public transport can link Liverpool city centre with Manchester airport at antisocial hours, why can't it link Liverpool with it's own airport!?
While its true that the failing economy has adversely impacted on LPL, I feel that they have done themselves no favours. LPL is a great little airport once you are there - the revamped security area has massively improved the experience in recent years. However, now that the sleeping giant up the road has woken up to the loco revolution, LPL needs to make things easier for it's potential customers.
A collective effort to make the airport more accessible early morning and late at night would be a good start. I find it hard to believe that the N86 lost money, but if it did, surely it is worth subsidising? Surely cheap, convenient access to the airport will generate far more in airfares than the initial cost?
A combined rail/bus ticket would also help - passengers catching the train should be able to buy a single ticket that takes them directly from their point of origin to the airport via Liverpool South Parkway. This could open up the North Cheshire/ Midlands catchment area more effectively (an area that is relatively poorly served by rail from MAN). Long term, the council should make a rail connection to the airport a priority - I'm always struck by similar sized airports in Germany that have dedicated rail links (e.g. Berlin SXF, Nuremburg, Dortmund). If it works there, why not here?