LONDON, Jan 23 (Reuters) - Britain"s Queen Elizabeth flew by helicopter to her Sandringham estate in East England on Sunday after delaying her traditional Christmas trip for a month due to COVID-19, a Buckingham Palace source said. The queen flew from Windsor Castle to the residence in Norfolk, where she had spent Christmas with members of her family for decades before the pandemic struck in 2020. The 95-year-old monarch has been at Windsor Castle to the west of London for most of the pandemic. read more She will celebrate her Platinum Jubilee, marking 70 years on the throne, this year.