I hear you – same here. One wonders, how much of the price difference are fuel and airport subsidies to airline companies. If that much tax-payer money has to go to flying to make it affordable, I'd rather it was allocated to the railway. Far more humane, less noisy, less hassle, far lower carbon footprint, far more pleasant.
@albertcardona @villavelius you have to access sites of different companies (sncf, renfe, eurostar) and can book many of the lines. Of course it is costly, but you can get there in 2 days. Personal experience: everything booked but the Eurostar/Thalys, because these tickets where only available 3 months in advance. Or the night train from Hamburg to Stockholm, only 6 weeks before departure, while regional trains in Sweden were already fully booked by that time...