You've probably heard that the TSA has lifted some restrictions on what you can and cannot carry on board an aircraft now.  Pretty soon, scissors, small tools, and other sharp objects will be once again allowed in the cabin.
Presumably, this is so the TSA can focus on the "far larger threat" of explosive devices being smuggled aboard, either by passengers or in the cargo hold.
But is that really a threat?  I didn't think it was credible, so I did some resarch.  You'd think if this was a big deal, planes would be blasted out of the sky on a regular basis, right?
Well, you'd be wrong. 
The last bombing of any kind happened in 1997 in Brazil.
The last American airliner to be felled by a bomb was over Lockerbie, Scotland back in 1988.  The last one that was destroyed over the continental United States was in 1962.
Here's the full list of aircraft that have been destroyed in flight by a bomb:
04.11.1955 Air India                        Lockheed L-049, Great Natuna Island, Sarawak        
11.01.1955 United Airlines                Douglas DC-6B, Longmont, Colorado, USA
07.25.1957 Western Airlines                Convair CV-240, Daggett, California, USA        
01.06.1960 National Airlines                Douglas DC-6B, Wilmington, North Carolina, USA        
05.10.1961 Air France                        Lockheed L-1649A, In Amenas, Libya        
05.22.1962 Continental Airlines        Boeing 707-124, Unionville, Missouri, USA    
07.08.1965 Canadian Pacific Airlines       Douglas DC-6B, Dog Creek, B.C., Canada    
11.22.1966 Aden Airways                Douglas DC-3, Aden, Yemen        
10.12.1967 British European Airways        de Havilland DH-106 Comet, Rhodes, Greece         
12.22.1969 Air Vietnam                        Douglas DC-6B, Nha Trang, Vietnam        
02.21.1970 Swissair                        Convair CV-990, Zurich, Switzerland         
04.21.1970 Philippine Airlines                Hawker Siddeley HS-748, Manila, Philippines         
11.21.1971 China Airlines                Sud Aviation SE210 Caravelle, Penghu, Taiwan        
01.26.1972 JAT Yugoslav Airlines        McDonnell Douglas DC-9-32, Hermsdorf, Czechoslovakia   06.15.1972 Cathay Pacific Airways        Convair CV-880, Pleiku, Vietnam     
03.19.1973 Vietnam Airlines                Douglas C-54D, Ben Me Thuot, S. Vietnam    
04.21.1973 Philippine Airlines                Hawker Siddeley HS-748, Patabangan, Philippines        
05.25.1973 Aeroflot                        Tupolev TU-104A, Chita, Siberia    
12.18.1973 Pan American World Airways      Boeing 707-321C, Rome, Italy        
09.08.1974 Trans World Airlines        Boeing 707-331B, Ionian Sea        
01.01.1976 Middle East Airlines        Boeing 720-023B, Al Qaysumah, Saudi Arabia    
10.06.1976 Cubana de Aviacion                McDonnell Douglas DC-8-43, Bridgetown, Barbados        10.13.1976 Indian Airlines                Sud Aviation SE210 Caravelle, Bombay, India        
12.21.1980 Transportes Aereos del Caribe   AƩrospatiale Caravelle, Rio Hacha, Colombia        
09.23.1983 Gulf Air                        Boeing 737-2P6, Mina Jebel Ali, United Arab Emirates    
06.23.1985 Air India                        Boeing 747-237B, Atlantic Ocean - off Shannon, Ireland        
04.02.1986 Trans World Airlines        Boeing 727-231, Athens, Greece    
05.03.1986 Air Lanka                        Lockheed L-1011-100, Colombo, Sri Lanka    
11.29.1987 Korean Air Lines                Boeing 707-3B5C, Andaman Sea    
03.01.1988 Comair (South Africa)        Embraer 110 Bandeirante, Johannesburg, South Africa      12.21.1988 Pan American World Airways      Boeing 747-121, Lockerbie, Scotland        
09.19.1989 Union des Transports Aeriens    McDonnell Douglas DC-10-30, Bilma, Niger        
07.19.1994 Alas Chiricanas                Embraer 110 Bandeirante, Colon, Panama        
12.11.1994 Philippine Airlines                Boeing 747-283B, Pacific Ocean
07.09.1997 TAM Brazil                        Fokker F-100, Suzano, Brazil
The raw data for this search, including accident details, number of persons killed, and aircraft registry information is available 
here. (Pay no mind to aircraft lost in BOMBay, or any BOMBardier on the list. )
And in the interest of "fair and balanced", here's a similar 
raw list for all aircraft that have been lost as a result of a hijacking.
And I need not remind you what happened the last time you could 
fly with boxcutters, right?