I am sure your training will have some form of tax advantage and possibly some government incentive or kickback. It will not cost the company £20k. If the training cost is reduced, I am sure the company would rather have a high turnover of staff. Historically, newbies cost less, a large majority have a short term aim and do not necessarily see the job as a long term career, do not join the union as it is £8ish a month and are easier to push around.
As for the spending on the clubhouse and the 787 - The company have to invest in new aircraft and decent lounges to attract the premium business that pays our wages. We would lose the higher paying passenger if all we offered was instant coffee and a ride on a rickety old 747 classic that spent most of its time in the hangar. With the price of fuel, 4 engines is no longer the way ahead. To survive things have to change.
The weak dollar works both ways. It may be cheaper to shop in Abercrombie in the states if you are flying from the UK. However, equally if an American wants to have scones in York, the weak dollar makes it more expensive for the return business. In addition, due to the lack of a welcome and the premise of we are all terrorists until proven otherwise, I am sure that the overall number of holiday makers visiting the states is down.
I believe that you deserve a pay rise but again you are clouding it with a seperate issue. Hold out for what you believe you are worth - the fact that the company is investing in facilities and aircraft to remain competitive is irrelevant.