Pollard is staying with ABTA on an interim basis as head of European development to represent the body in Brussels as a key EU directive on package travel goes through.
Labour Party members in the Plymouth constituency of Sutton and Devonport selected him as their general election candidate on 30 June.
D’Alfonso will head a team of four public affairs staff at ABTA, reporting to chief executive Mark Tanzer.
Pollard has been head of public affairs at ABTA since late 2009, while D’Alfonso joined in 2010.
Tanzer said: ‘ABTA has made considerable progress in growing its political influence in the UK and in Brussels in recent years.
‘I am confident that with this new structure we will continue to have a first class team working on behalf of ABTA and our members in Whitehall, Westminster and Brussels.’