There was so much goodness packed on to the plane there was almost no room for me. I had a boarding pass but by the time I got to the gate every seat was filled. This was American Airlines flight 575 from Miami to Port-au-Prince and the passengers were on a mission to help Haiti. A volunteer agreed to take a later flight and I squeezed on.

The front rows had people in orange T-shirts, further on there were blue ones and at the back lime-green, each with a Haiti-related logo. Instead of the in-flight magazine, people were reading engineering manuals, budget reports, the Bible and books with titles such as Touching Them Now and Forever.

Spirits were high. We were on our way to another world, which would provide a sense of purpose, not to mention adventure. "Welcome aboard!" beamed the steward. Two hours later, as we trooped off into blinding Caribbean sun, the steward was still beaming. "Bye bye!"

I was too depressed to smile back. During the flight I had been reminded by the passenger seated beside me how do-gooding outsiders can screw up Haiti. What made it all the sadder was the fact he was nice, decent and humane. It is harsh to identify Ed Hettinga and his group, Mission to Haiti Canada, as exemplars of an unfolding tragedy. Each member was coming on his and her own time and dime (air fare alone, £980) and was almost certain to improve the lives of some Haitians.

Villains in Haiti's suffering include France, which crippled its former colony with two centuries of immoral debt; the US, which bullied Haiti to cut food tariffs, swamping the country with US imports and destroying homegrown agriculture; donors who have welched on funding pledges; and Haiti's political and business elite, cocooned in luxury and indifference.

But what about people such as Hettinga, a retired dairy farmer from Ontario who is treasurer of a well-meaning non-governmental organisation? Where other westerners wring their hands, he wraps his around buckets of cement and builds houses. Hettinga can be admired, and his heart is in the right place. But in Haiti's ongoing disaster, his NGO – and thousands of others – is one reason why so much international goodwill has added up to so little.

Mission to Haiti Canada, founded in 1997, raised £32m after January's earthquake for medical treatment, drugs, housing and to run six schools and an orphanage. "We are faith-based but non-denominational," said Ed. "We don't evangelise and don't care if people are voodoo or whatever. We just want to help."

In April a team of 28 Canadians and 38 Haitians built a hurricane-proof two-room house. "It cost $6,000 and we did it right, just like back home. Why should we expect people here to live in garbage?" says Hettinga. The plan was for locals to build dozens more. "We're teaching them. The idea is to be self-sustaining." The NGO spent $10,000 shipping a container with three big tents, clothes, rice and beans. They felt they were filling a vacuum left by a useless, predatory state.

Sounds noble, but consider this: more than 1 million homeless people urgently need housing. Here you can build a decent home for a fraction of what the Canadians spend. The group, which does not speak Creole, relies on a young local fixer to select beneficiaries, disburse funds and keep records. Locals have no realistic way to build in the absence of occasional Canadian visitors. The group has zero contact, and therefore no coordination, with the housing, health or education ministries. Hettinga's cheerful countenance briefly clouded as he acknowledged some problems. "As soon as we leave, everything stops. You try to teach . . . but really you just touch the people you deal with directly."

Better than nothing? Consider that this picture is multiplied across Haiti via more than 9,000 organisations. It is a republic of NGOs. Most are not registered, pay no tax and are not accountable. They shun cost-benefit analysis but soak up aid money, saying Haiti's state is incompetent and corrupt. The latter may be true but is a self-serving argument, which starves the government of resources and legitimacy, creating a vicious circle of dependence and institutional infantilism.

How can Haitians make policy when foreign-run fiefdoms suck up funds for pet projects? How can local farmers harvest crops when free food floods markets? These questions were far from the minds of the passengers of Flight 575 as they spilled out of the plane rubbing their hands with anti-bacterial gel and shooing away tip-hungry porters. "I'm just here for the ride," grinned an amiable, skinny teen from Kentucky's Grace Foundation. "I'm not sure what we're going to do. Build a wall, I think, move some concrete."

There are some professional NGOs that are registered and do excellent work – Christian Aid, MSF and Oxfam, among others – but despite jargon about "capacity building" they too breed dependence. The solution is not for all foreigners to pack up and leave. Haiti needs NGO help. But it also needs to rein in aid tourists who turn the country into a zoo and to fold the serious NGOs into a coherent, Haitian-directed strategy. Fingers crossed the 28 November election produces a strong government to start the process.