airline would put on another flight
Did the airline say this? I don't work for SAS, but my current airline and the previous one flies seasonal flights that once fully booked, that's it. We don't put on more flights just because the previous one is sold out - we don't have the equipment or the crew for that.
If the airline said they'd put on more flights, then I might get concerned as to why they've not done so. If they didn't say that, then I'd think it's going to be a very cozy flight!