I don't think an FBI contracted plane would be involved in a possible natural ecological event. They, the USGS, have their own planes, and much better equipped with aerial "electronic sniffers"
Besides which, the photo clearly shows a camera pod.
Whoever they are... IF the mystery plane is looking for the source of the mystery odor
[they both mysteriously appear around the same time]... maybe they haven't considered
an offshore methane hydrate origin. The reason I do is because I have been expecting
[and posting] about a methane hydrates "event" on the east coast for 10 years.