Queen Elizabeth is telling Prince William to smarten up.

With health concerns and ever-changing plans for Christmas, the 95-year-old monarch has a lot on her mind these days. But one thing above all "keeps the Queen awake at night," according to a new report. It's William's use of helicopters.

Queen to Prince William: No more family helicopter trips

The Queen is said to be "very worried" about recent helicopter trips taken by Prince William and his family between their homes in London and Norfolk.

A source told The Sun this week that the Queen "knows William is a capable pilot but does not think it is worth the risk for all five of them to carry on flying together."

Prince William is a trained pilot. The Queen says no family trips.

The Queen has apparently voiced her concerns to friends, Palace staff, and even William himself, whom she told: "Bad weather and accidents can strike at any time."

If the unthinkable were to happen, the Queen fears it would "spark a constitutional crisis." Of course, Prince William is a future king and is second in line to the throne.

William's son Prince George follows his father in the line of succession, with his siblings Princess Charlotte and Prince Louis coming after.

The Sun report added that the Queen "knows the monarchy is safe" in the hands of the Cambridges — who, by the way, just released their annual Christmas card last week.

But it sounds like Queen Elizabeth would sleep easier if her grandson, who is a trained pilot, ended the convenient but risky air travel with his family.

After William and his kids, Prince Harry and his children stand in the following three places in line to the throne.

The Queen's thoughts on a future with Prince Harry as king were not mentioned in the new report, however.