The Argentine Civil Aviation Administration recently announced that all general aviation traffic and commercial flights operated by aircraft with fewer than 31 seats will be banned from Buenos Aires Aeroparque (AEP), effective 30Nov12. The only exception to this will be official government flights, such as the president's aircraft, and declared emergencies. Air taxi companies and FBO's (fixed base operators) that are based at Aeroparque will be allowed to operate out of AEP until 31Jul13.
This means that small airlines such as Aerochaco and LAER that use 19-seat Jetstream 32's will have to move their operations north to San Fernando (FDO) if they continue service at all. Sol operates Saab 340A's and 340B's that have between 34-37 seats so they meet the 31-seat cutoff and will presumably be allowed to continue operating from AEP.
The reason behind the measure is the "saturation" of the airport from an air traffic standpoint since regional international flights were introduced at AEP in early 2010 plus the growth of domestic flights at the airfield in recent years.
I have been to Aeroparque many times in recent years to spot and take photos and far from perceiving the airport to be a very busy place it has struck me as having relatively little traffic for one of two main airports of a major cosmopolitan city.
Compared to some other major one-runway airports, Aeroparque does not seem especially busy. 8.25 million passengers travelled through AEP in 2011 and the airport has 295 daily movements by commercial airlines. By comparison, San Diego (SAN) had 16.8 million passengers in 2010 and has 342 daily commercial flights and London-Gatwick (LGW) had 33.6 million travellers in 2011 and has 550 daily flights, nearly double Aeroparque's. I suspect the difference is explained by greater investment in equipment and infrastructure. Rather than turn away aircraft, it would be better to invest more in AEP, which is an important contributor to the Argentine economy.
Wikipedia re Sol Saab 340's, SAN, and LGW