Research by Scottish Labour found a return flight from Edinburgh to London Stansted could cost as little as £29.98 - less than the £31.40 price of a peak-time ScotRail ticket between Glasgow and Edinburgh.
As they clearly state in that text, a poor comparison is being made. Comparing radically different products, with the lowest possible cost of one of them compared to the highest possible cost of the other!
When I go to the online booking engines for the next few days ... and you will note I have only single fares here Edinburgh to Stansted. As I write, the lowest cost single airline flight southward is 10th January 2025 at £14.99
Edit to add with luggage to add £29.98 or £39.48 (single) for "essentials" or "standard plus". If you don't someehere from £6.40 to £18.99 so select a seat (yes, there is a skip button). There are four days available in the following week for you to return at the £14.99 fare.