There are domestic flights within Scotland, but it's hardly worth the price unless there's no other option. Buses are thick on the ground.
Scotland's train routes are picturesque but somewhat limited and expensive. Driving around Scotland is generally easy and far less busy than in England, although petrol stations may be few and far between (as well as pricey).
If you want to hit the water, boats run to most of the islands or you can get a ferry from Aberdeen to Orkney or Shetland.
Only British Airways and its subsidaries offer domestic flights in Scotland, and it's hardly worth the price unless there's no other way to get to the islands.
Scotland's train routes are stunning but limited and expensive.
Haggis Backpackers bus service runs between Scotland's youth hostels, as does Macbackpackers. Citylink bus company (Scotland's major player) has a tourist pass which can be used on all their buses.
Roads are generally good and far less busy than those in England. On back roads you may have only one lane and petrol stations may be few and far between (as well as extremely pricey).
Boats run to most of the islands from Oban, Mallaig and Ullapool, or you can get a ferry from Aberdeen to Orkney or Shetland.