Do the Marines still have Hornet squadrons on carriers?
As part of the Navy-Marine Tactical Air Integration plan (the official name), there will be a Marine VFMA squadron (single seat) attached to each Air Wing. Additionally, 2 or 3 Navy VFA squadrons (C's) will be put in the UDP cycle (deploy with the Marine MAG's).
Why are they doing this? The official reason is to better integrate Navy and Marine aviation to counter the threats to the US, to make us better warfighters, or something along those lines.......The real reason is money. The Navy and Marine Corps cannot sustain the number of Tacair squadrons that we have now and this allows them to cut back. Some of the thinking is that if they really need the Marine Hornets for the Marines they will pull them off the Air Wing's temporarily. Some links:
Congressional Research Service Paper (PDF):
http://www.fas.org/man/crs/RS21488.pdf
GAO evaluation of the plan:
http://www.gao.gov/docdblite/details.php?rptno=GAO-04-900
National Defense Magazine Article:
http://www.nationaldefensemagazine.org/issues/2003/Jan/As_details_of.htm
Quotes from GAO eval:
Under this Plan, the two services will perform their missions using fewer units of more capable aircraft and reducing total program aircraft procurement costs by $28 billion over the next 18 years.
The Plan also reduces the services' tactical aviation force structure by decommissioning five squadrons, thus decreasing the number of Navy and Marine Corps squadrons to 59, and reduces the total number of aircraft they plan to buy from 1,637 to 1,140.
In a related note, the Navy plans on reducing the number of planes per VFA squadron from 12 to 10. Again, saving money.
If you don't think the Navy is hurting a little bit for money, I just saw in hte news that the Navy will dip below 280 ships next year

. Wasn't it just a few years ago we were trying to get to a 600 ship Navy? It really is not suprising when the proposed DDX will cost somehting at least $1.7 billion a ship (maybe up to $3 billion when you cout in all of the costs of the program).
http://www.globalsecurity.org/military/systems/ship/dd-x.htm