Back in 1998 when I was 17 years old I was entered for a flying scholarship with the RAF. I attended a one-on-one interview at my local careers office and was shortlisted to attend Officer and Aircrew Selection Centre (OASC) at RAF Cranwell, where flying scholarship candidates undertake a shortened version (including flying aptitude, interviews, and a full medical) of the full selection tests.
At the end of the third day I was told that although I more than met the requirements for aircrew, my legs were 14mm too long, and I was declared permanently unfit for aircrew duties. I was offered a chance to become an officer in any other branch of the RAF except for aircrew. Since being a pilot was the only thing I was interested in, I declined. Of the 34 people who attended OASC with me, only two passed the tests for aircrew.
You will be asked at various stages of the selection and interview process what type of flying you wish to do, and what aircraft. The choices in the RAF are: fast jet (i.e. Tornado, Harrier, Jaguar, Typhoon), multi-engine (Hercules, Nimrod, Sentry, VC10, Globemaster, Tristar), or rotary wing (Puma, Merlin, Sea King, Chinook). I believe candidates are placed into different streams early on in their training, and the decision is made based on your flying strengths and weaknesses, and also on the requirements of the service.
As for the training, well from what I remember for the fast jet stream....
Upon successful completion of the tests at OASC you would attend RAF College Cranwell for 6 months or so, where you will undergo your officer training. Once that is completed you will begin your pilot training. If you already have a PPL you are allowed to skip the elementary training (currently on Grob Tutors, undertaken by all trainee pilots in the UK Military) and progress straight onto basic training. I believe basic training for fast jet pilots in on the Shorts Tucano. Once this is completed you progress to fast jet training on the BAe Hawk. Upon completion of this training, you progress to weapons and tactical training, again on the BAe Hawk. Once that is done you "get your wings" and will be appointed to an OCU for the type you will eventually fly e.g. Harrier, Tornado, etc. Once you have completed the training at the OCU you would be assigned to an operational squadron.
To cut a long story short I ended up becoming a marine engineering officer in the Royal Fleet Auxiliary Service. I just spent some time on RFA Gold Rover in the South Atlantic. When we were in the Falklands I would quite often take the opportunity to travel up to the Joint Officer's Mess at Mount Pleasant because the food up there was much better than what we had on the ship. The Mess was used by all three services, and I came across the RAF Tornado F.3 aircrews who are stationed at Mount Pleasant. Seldom have I met such a collection of egotistical tossers. Ever heard the joke "How do you know a pilot just walked into the bar? He'll tell you." Well, I now fully appreciate where that joke come from.
So, to answer your question....
The chances of actually becoming a pilot in the RAF. Slim. Very slim. They have no shortage of candidates, and they can afford to be very fussy. However, if you make it through, then great, you've achieved a dream. The only advice I will give about joining the military is make sure you pick a trade that has skills that are easily transferrable to a civilian job. The time will come when you want to leave, and if you don't have any skills or experience that will be of benefit to you in civvie street then your time in the military will be of very little value.
As for the "honor and duty" stuff, well... it's a load of rubbish. I can tell you that when I was rocking and rolling in heavy seas in the South Atlatic I wasn't thinking about honour and duty. It's all about doing something worthwhile with your life, so when you're an old man you can say "I've been there and done that." It will make you a more rounded individual, you'll see life and its trials and tribulations in a different light, and best of all you'll find good mates and good times.