INSTRUCTOR WITH STUDENT IN SMA CLRED AREA BUT SHORTLY INTO TKOF ROLL HAD 2 SMA ACFT PASS OVERHEAD ONE ON EITHER SIDE. RPTR PROTESTS CLOSE PASS BY THE 2 ACFT.

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PRIOR TO ENTERING RWY 04 AT ZZV FOR A STUDENT TRAINING FLT IN AN SMA WE MADE A L HAND 360 DEG TURN TO CLR THE PATTERN FOR TFC; HELD SHORT OF THE RWY TO CLR FINAL; ANNOUNCED OUR INTENTIONS TO DEPART RWY 04; TAXIED ONTO THE RWY AND BEGAN A TKOF ROLL. SHORTLY INTO THE TKOF ROLL; 2 SINGLE ENG HIGH WING TAILWHEEL ACFT PASSED OVER US; 1 TO EACH SIDE OF THE RWY AT WHAT I CONSIDERED EXTREMELY CLOSE TO US AND TO 1 ANOTHER AT AN UNUSUALLY LOW ALT NO FURTHER THAN 50 FT AGL. WE IMMEDIATELY ABORTED THE TKOF AND EXITED THE RWY. 1 ACFT MADE A TIGHT L TURN AND LANDED ALMOST IMMEDIATELY AFTER WE HAD TAXIED CLR; THE OTHER ENTERED THE PATTERN AND LANDED SHORTLY AFTER. AT NO TIME PRIOR TO OUR ENTERING THE RWY DID WE RECEIVE ANY RADIO TRANSMISSIONS FROM TFC INBOUND OR IN THE PATTERN AT ZZV; AND NO ACFT WERE VISIBLE TO US WHEN WE CLRED THE AREA PRIOR TO ENTERING THE RWY. I DID NOT SEE EITHER ACFT UNTIL THE FLEW OVER US; APPARENTLY IN FORMATION. I BELIEVE THAT NEITHER ACFT WERE FLYING A STANDARD TFC PATTERN AND THAT AND THE FACT THAT NEITHER GAVE A POS RPT OVER THE RADIO CONTRIBUTED TO MY AND MY STUDENT'S INABILITY TO SEE THEM PRIOR TO ENTERING THE RWY AND RESULTED IN THE INCIDENT. I BELIEVE THAT THE INCIDENT COULD HAVE BEEN AVOIDED IF STANDARD TFC RPTS HAD BEEN MADE AND (PARTICULARLY IN THE CASE OF A NO RADIO ACFT) A STANDARD TFC PATTERN HAD BEEN FLOWN. MORE EMPHASIS ON STANDARDIZED TFC PATTERN PROCS AND RPTS; AND ADHERING TO CURRENT PUBLISHED PROCS MAY HELP AVOID FUTURE INCIDENTS SUCH AS THIS ONE.