No, you shoudn't because it is part of the United Kingdom.
No
You are most likely to fly over the Scottish mountains on a flight from London Heathrow to Aberdeen Scotland.
You can fly from London to San Francisco without flying over Scotland on the plane by flying from London to Portugal first. You might also fly from London to Paris and then from Paris to San Francisco.
A flight flying between these two locations will firstly fly north towards Central London, then further north over Hertfordshire and Bedfordshire towards Nottingham, then the flight will fly past Sheffield and then over much of the Pennine Mountains before crossing the Scottish border, after the plane crosses the border it will fly north over the Central belt of Scotland and then over much of the Highlands before descending into Inverness.
No
no
You could fly, drive or take a train.
They would fly over Ireland.
Inverness is the nearest airport to Loch Ness and a flight from Glasgow would take about 30 minutes.
Nobody requires a passport to travel between London (England) and Scotland, as both are part of the UK.
no