Flights arriving at Boston Logan International Airport Sunday with occupants suffering from “various illnesses” prompted alerts to the CDC.

Another aircraft collision at Boston Logan International Airport (BOS) in quick succession has raised concerns about proper adherence to on-ground protocols. This came just a day after two planes belonging to American Airlines and Frontier Airlines clipped wings at the airport.

Officials at Boston Logan International Airport contacted the CDC after “various illnesses” were reported on incoming flights on Sunday. The Delta and Avianca flights, which originated in different cities, arrived in Boston at around the same time Sunday afternoon as strong gusty winds whipped around the region.