By Guy Taylor Heathrow Airport has retained its crown as Europe’s busiest airport over the first half of the year as passenger traffic broke records multiple times in July. Some 8m travellers passed through the West London hub over the month, millions more than the likes of Amsterdam Schiphol, Frankfurt, Madrid and Paris’s Charles de Gaulle. Heathrow saw six of its busiest ever departure days in the as the school summer holidays kicked off, with over 140,000 direct passengers leaving the airport each day despite disruption from July’s global IT outage and environmental protests. The airport ha…