Most commonly you want to go from city center to city center. Airports are outside, so you have to get there. that takes time. Then you have security checks, boarding and so forth, which takes hours. If trains are reasonably fast trains are faster at something like 500km, for really well built high speed rail you end up at 1000km.
As for cost, as the article explains, trains have to pay fuel taxes and VAT, which flights do not. The price difference is low enough, that that would make trains cheaper or at least as expensive as planes on many journeys.
Most commonly you want to go from city center to city center. Airports are outside, so you have to get there. that takes time. Then you have security checks, boarding and so forth, which takes hours. If trains are reasonably fast trains are faster at something like 500km, for really well built high speed rail you end up at 1000km.
As for cost, as the article explains, trains have to pay fuel taxes and VAT, which flights do not. The price difference is low enough, that that would make trains cheaper or at least as expensive as planes on many journeys.