difference between explain plan and execution plan

The explain plan is what the optimizer thinks will happen when you run, the execution plan is actually happened when you ran the query.

See link here.

http://tkyte.blogspot.co.uk/2007/04/when-explanation-doesn-sound-quite.html

explain plan is the statement that is used to display the execution plan.

The two samples you have shown are just formatted differently, that's all.

You did not tell us how exactly you generated those outputs nor which tool you were using.

But if'm not mistaken, one of them is the output of an autotrace inside SQL*Plus the other the output when using of of the procedures of the dbms_xplan package.