Thistles and her group weren't anywhere near where Kate's team was now. They were about 3 miles away already; going at around 60 miles an hour through the air and about 850 feet above the ground.
Thistles flew calmly through the dry, cold air of the arctic, checking up on Pacu occasionally to make sure he was well. The 2 clones behind her were carrying the food, and the 3 behind them were carrying wood and pick.
At about 1,500 feet into the air, Thistles stopped looking straight forward and stared at the sky instead. She had a worried look on her face as she stared at it.