Bournemouth Aviation Museum for making all these experiences possible for a really low entrance cost.
Staffed by friendly and knowledgeable volunteers and stuffed with cool planes to play in and admire, this is the first place my kids ask to go to when visiting my folks. My favourite is the PalmAir fuselage you can walk inside, complete with displays about the history of the airline.
The displays of vehicles at places like the Science Museum are really interesting, but all the 'do not touch' signs, necessary as they may be, make the experience a lot less fun for the kids. The active encouragement for visitors to explore the exhibits at Bournemouth make this a fairly unique experience and one which has the kids begging to go back time and again.
The site is family friendly, with toilets and well maintained grass that is easy to push a buggy on. Access to exhibits is often by steps, necessarily, and it's up to parents to keep kids under close supervision, especially when climbing up into cockpits high off the ground. There picnic bench seating provided should you wish to take a break and a small gift shop for bringing home pocket money toy planes or other memorabilia of your visit.