LONDON (Reuters) - British Airways planes could be seen parked up at London's Heathrow Airport on Thursday, as the airline begins the process of grounding a large part of its fleet.Air travel is grinding to a halt due to coronavirus, and BA's boss warned last week that the airline was in a battle for survival and would have to cut jobs and park up its planes.The park-up is now under way, with more aircraft expected on the ground at Heathrow, BA's hub, in the coming week. There are more than 280..