Pat Derby, co-founder of the Performing Animal Welfare Society has been working for two years to get the elephants in the air.

The African elephants, Iringa, 42, Toka, 41, and Thika, 31, are being moved to PAWS' 2,300-acre facility.

Prior to the flight, the animals had to undergo crate and noise training. A Russian cargo jet and two fleets of trucks had to be rented.

Special pilots, drivers and crews were also hired.

Crates were designed and fitted for each elephant; hydraulic gates reinstalled at the sanctuary; and barn space cleared.

Former game show host and animal activist Bob Barker is paying the bill, which is estimated to be between $750,000 and $1 million.

"We rattle the crates and make all kinds of sounds so they are used to noise," Derby told The Associated Press, because "there are no test flights."

Iringa and Toka do have past plane experience - they were flown to Toronto from Mozambique 37 years ago. Would an elephant forget?

The elephants fit cozily in their crates and will be tethered so they don't get hurt on the way, Derby confirmed.

The Russian cargo plane is bigger than a C-17 so will fit all three elephants easily, along with keepers from Toronto and crews from PAWS.

Derby further added "You want them to have full capacity and be fully aware of everything that's going on. It's not a good idea to tranquilize any animal because they can flop around and get sleepy and go down. They need to be awake and conscious and able to shift their weight and behave normally."

The three animals are expected to give each other company on the way. So one could expect trumpeting.

"They make sounds we can't even hear, low rumbles and sonic sounds. They will be talking to one another through the whole flight, I am sure," Derby said.

The elephants will be in their crates when they leave the Toronto Zoo on trucks, during the flight and during the truck trip from San Francisco to San Andreas, 125 miles northeast.

The trip is estimated to be about 10 hours long.

A truck trip would have cost less but would have taken over 40 hours without stops or traffic, which did not seem like a good idea.

At the sanctuary, they will meet their new companions Lulu, 47, Maggie and Mara, both 28, from zoos in San Francisco, Alaska and San Jose, respectively.

"You have to provide them with the opportunity to socialize, as well as the ability to retreat if frightened," Derby said.

Reportedly there are three female Asian elephants and two Asian bulls at PAWS but the Africans and Asians are separated.

"They appear to be sweet, lovely, tractable elephants and I'm just excited to get them integrated into our group so they can have a wonderful social life. Our three girls have missed being in a larger group," Derby said.

It's hard to guess on the longevity of these animals, especially when in captive.

In the wild, 50-year-old female elephants are still having calves, but none of the animals at PAWS will ever be bred.

"To breed them in captivity is criminal," Derby said.