PORT-DE-PAIX — Residents in Haiti’s Northwest are growing increasingly frustrated as construction of the Port-à-l’Écu International Airport remains at a standstill, nearly two months after authorities announced plans to relaunch the long-promised, 20-year-old project. The plan to build an airport with international standards in the coastal village less than 20 miles west of Port-de-Paix, the capital city of the Northwest Department— promoted as …