Is chartering a private aircraft cheaper than flying commercial?

In a word: NO.
Private aviation, usually, cannot compete in price with the airline industry. Private charter allows you to reach remote destinations, avoid TSA agents and busy terminals, lost baggage, and cancelled flights but it has a cost associated with it.

Does Monarch Air Group have Google Chrome extension?

Yes. For our client we have developed Google Chrome Extension, which you can download for free – Monarch Air Group Extension.

What is an empty leg flight?

An empty leg flight occurs when a private jet is booked for a one-way flight and has to return to its base for repositioning but has no passengers for the return flight.