It began with a show of hands. Laura Mueller of Airfinance Journal asked a crowd of a few hundred aviation leaders at this Monday’s conference for IBEC’s Aircraft Leasing Ireland’s Global Aviation Sustainability Day whether they believed their industry would achieve net-zero carbon emissions by 2050. A lot of hands shot up, but it wasn’t a clear majority. Mueller then turned to Willie Walsh, the former chief executive of IAG and head of the powerful International Air Transport Association (IATA), which represents over 300 airlines, for his view. “The sceptics are definitely wrong,” Walsh said.  “We have no choice. It’s…