Once again, smoke from the Canadian wildfires has drifted south, impacting visibility, air quality, and flight schedules on the east coast of the United States. Wednesday evening was beset with numerous delays to and from LaGuardia and Newark Liberty International airports. Thursday morning saw over 4,200 delayed flights across the U.S., with the FAA also temporarily suspending inbound traffic to Philadelphia International Airport. Holiday travel ahead of Independence Day begins this weekend with 4.17 million Americans expected to fly to their destinations; a portion of which will likely be affected by air quality and inclement weather, though officials expect that conditions caused by the smoke shouldn’t be as intense as earlier in the month.