Mr Branson does not say anything innovative here but there are town things they sand out, two things others forget but are home truths.
First you want to think outside the box ensure you don’t get in one in the first place, this is much harder than it sounds and can be challenging but is often the key to really great idea.
Second, define the problem and not the solution, this can be challenging too, this is part of the box problem people run towards the nearest solution they can find, thus putting themselves deep into the box. Use 5 whys and various other techniques to define the problem, then take a bread and go for crazy ideas. 6 thinking hats and think pack are helpful here.