I know it is a long shot for a free piece of software like this - is it on the hitlist to flag up a duplicate sighting

What do you mean? Like on your list of sightings? Because when you search for a registration number, it shows you with the little icon on the left if you've already seen it.

Yes that's what I mean - I tend to go straight to add multiple sightings

Hi Nandoman,

We're always adding new features, so suggest away and we'll consider them.

Do you mean after you do a multiple sighting, you would like it to show a report, listing all the aircraft you've seen before, and all the ones that are new sightings?

Yes - something that flags an already seen aircraft - but guess some may want to show various locations they have spotted an aircraft

Sounds good to me...I don't get around as much as the OP, so probably not as useful to me, but I can see what he's getting at and I'm sure some other users would really like that too.