First thing, if you're flying by yourself then you may have less hassle in regards to worrying about sitting next to your companion at all times, as this is not a guarantee.
When taking a helicopter flight by yourself you could upgrade to sit in the front seat if circumstances allow it, though there is an upgrade price to pay if they don't sit you in the front seat originally.
Taking a flight by yourself will result in you sitting with strangers, though other passengers may be in a similar situation to you.
When choosing to take a flight by yourself, know this does not put any restrictions or prevents you flying at all - if you book up you will be entitled to fly regardless.