OVERLAND PARK, Kan. (AP) _ American Carriers Inc. officials say they are puzzled by a proposal by Baytree Investors Inc. of Chicago to acquire 80 percent of American Carriers, an Overland Park-based trucking company.

American Carrier officials said Wednesday that the offer was ''confusing'' and incomplete. American Carriers employs about 11,000 people nationally and about 300 in its corporate office and trucking operations in the Kansas City area.

Baytree, an investment company, has gone to federal bankruptcy court to acquire P.I.E. Nationwide Inc., one of the country's largest truck freight companies, and is being sued over its attempts to acquire a third trucking company.

Baytree's offer for American Carriers would be conditioned on acquiring at least 67 percent of the shares at a price to be negotiated and on approval by American Carriers' board of directors.

Baytree President Christopher A. Jansen said Wednesday that, under the proposal, the current management would control 49 percent of the company formed to own American Carriers.

American Carriers closed Wednesday at 6 3/4 , up 1 1/2 , on volume of 98,400 shares, which was three times more than the average daily volume in the summer.

American Carriers released a statement Wednesday saying that it had not solicited the offer and that it had several questions about it, Baytree and Baytree's principals, identified in the offer as Jansen and Gilbert K. Granet.

Among other things, American Carriers Chairman Leon H. Robertson said, the company wants to know whether the Baytree principals are or have been involved in litigation or securities law violations.

Jansen confirmed Wednesday that in 1983 he signed a consent decree with the Securities and Exchange Commission to refrain from certain securities activities and that he also was known as Christopher Jankowski. However, he said he didn't remember what the decree was about.

''I have no idea,'' Jansen said. ''It was quite a long time ago. I don't have it in front of me.''

He said his lawyers handled the decree, but he declined to identify them.

However, the Jan. 4 issue of Transport Topic, a motor freight trade publication, reported some of the allegations against Jansen and Granet that were included in a lawsuit filed by another trucking company.