http://flightaware.com/live/flight/DAL172
DL flight 172 from ATL to JFk
and
http://flightaware.com/live/flight/DAL1422
and
http://flightaware.com/live/flight/DAL458
and
http://flightaware.com/live/flight/DAL1987
Looks like holding patterns, if I assume correctly that you are talking about the ovular tracks, probably due to poor weather in the east backing traffic up, and ATC needing to space them out some more.
Are you sure these weren’t square dancing flights and they were doing a dosee-doo (sp?) enroute? 
They look mostly like weather deviations, but some routes (particularly out of western Florida) make you go a bit north before you get headed to the Northeast