It's true that you have to get to TLV airport fairly early to go through extra security checks. But with most airlines (I've flown Swiss, Lufthansa, El Al and... I can't remember, maybe something else?) once you clear security and immigration, you have plenty of time to browse in the duty free and do some last minute souvenir shopping before boarding. Air Canada seems to be the only airline with such a stringent boarding cut-off.

Perhaps it's that Air Canada uses a remote gate that you have to take a bus to get to? I honestly don't know. It's been a dozen years since I flew Air Canada out of TLV. Maybe someone who's done it more recently might have some insight?