Source : Webster's Revised Unabridged Dictionary (1913)

Overfly \O`ver*fly"\, v. t. [imp. {Overflew}; p. p. {Overflown};
   p. pr. & vb. n. {Overflying}.]
   To cross or pass over by flight. --Byron.

Source : WordNet®

overflow
     n 1: a large flow [syn: {flood}, {outpouring}]
     2: the occurrence of surplus liquid (as water) exceeding the
        limit or capacity [syn: {runoff}, {overspill}]
     v 1: flow or run over (a limit or brim) [syn: {overrun}, {well
          over}, {run over}, {brim over}]
     2: overflow with a certain feeling; "The children bubbled over
        with joy"; "My boss was bubbling over with anger" [syn: {bubble
        over}, {spill over}]
     [also: {overflown}]

overflown
     See {overflow}