Aside from all the other drawbacks mentioned above, I assume, amongst a million other things, that a big box with all the DVLA records and Companies House records would be slung over the border and Jimmie Krankie would be left to get on with it. The CAA would immediately rescind all airworthiness certificates for anybody based in or operating out of Scotland.
If Her Madge's forces were withdrawn, who'd stop the Ruskies flying their Bears where they wanted ?
Most people I know in industry, particularly those who live and work in their Scottish company's premises in England dread the thought of independence because they know that their income stream would stop right away. and they wouldn't get any more work from us.