Most tourists will find that the best options will be One-day cards for zones 1 and 2 during the week, and Weekend cards for zones 1 and 2 at weekends. There are lots of internal flights available in the UK, but by and large these are not the preferred mode of transport for native Brits. This is primarily because the country is so small that it does not normally take an unreasonable amount of time to travel to your destination by other methods, especially when you take into account time spent waiting in airports. Additionally it is also usually much more economical to travel by bus or train. But if your preferred method of getting around is by air, most travel agents should be able to help you find an appropriate flight.
Road networks are extensive and so travelling around by car opens up whole new areas to visitors.
And it also gives you the freedom to go where you want, when you want. But getting around by car is not without its drawbacks. The most obvious point to make is that in the UK you will have to drive on the left. It is also worth noting that the UK is a car loving country and so the roads are often very busy with traffic jams on the major motorways fairly commonplace. As a result you will probably have a much more interesting and enjoyable journey if you venture off the motorways onto secondary roads.