By Guy Taylor The UK’s largest airport group is weighing up adding Aberdeen, Glasgow and Southampton (AGS) Airports to its portfolio in a £1.3bn swoop, accordingto reports. Manchester Airports Group (MAG), the owner of Manchester and London Stansted airport, is set for a scrap for the three hubs with Spain’s Aena, which runs Luton airport, the Sunday Times reported. They will be joined by a group of Australian pension funds in pursuing AGS, which is valued at £1.3bn and was put up for sale by its owners Macquarie and the Spanish infrastructure giant Ferrovial earlier in the year. The move come…