Husting said while he would "rather not take" the journey, it would be "a 12-hour round-trip by train".
"I spend half my life on Skype and video conference calls," he said. "But as a senior manager, the people who work in my team sometimes need to meet me in the flesh."
From September, he would be making the trip only once a month and by train, because his team's restructuring would be coming to an end "and my kids will be a little older".
John Saven, the head of Greenpeace in Britain, wrote in his blog: "Well, it's a really tough one. Was it the right decision to allow him to use air travel to try to balance his job with the needs of his family for a while?
"Honesty and integrity to the values at the heart of the good you're trying to do in the world cannot be allowed to slip away. For what it's worth, I don't think we've crossed that line."
Richard Lancaster, who said he'd been involved with Greenpeace since the 1980s, responded: "I volunteer with Greenpeace but work in the commercial world and if I took a job in another country I'd expect to move to where the job is ... I find Pascal's travel arrangements almost unbelievable." Another supporter wrote: "So disappointed. Hardly had 2 pennies to rub together but have supported GP for 35+ years. Cancelling [direct debit]."
Greenpeace has campaigned to curb air travel and end "needless" domestic flights. In a briefing on aviation the group said: "In terms of damage to the climate, flying is 10 times worse than taking the train."