Olesen won the European Tour five times.
A court has heard that a woman was groped and urinated in the aisle on a British Airways flight in 2019.
The golfer was accused of being drunk and disruptive and swearing at the cabin crew.
Olesen has denied that he sexually attacked a woman, that he was drunk on an aircraft, and that he beat a second woman.
His trial began on Monday.
Olesen had been competing at the World Golf Championships-FedEx St Jude Invitation in Memphis before boarding a flight to London.
Olesen had no recollection of his actions on the plane after drinking and taking sleeping pills.
The woman who said Olesen had been "unsteady on his feet" testified in the case.
She said that he kissed her hand. He wouldn't let go. He put his head in the nape of my neck. He did not know what he was doing.
He had been aggressive towards crew members. He had his hand on my back. He moved his hand over my right breast. I was shocked. It had overstepped the mark.
Olesen appeared to be completely drunk and very sleepy, according to a member of the cabin crew.
She had never seen such bad behavior on a flight in 27 years of service.
The European Tour lifted Olesen's suspension.
She said she served Olesen two drinks on the flight.
She said she was aware that another passenger in the cabin was drinking champagne and that Mr Olesen was drinking from their glass.
Mr Olesen and his companion were in my attention. They were trying to have a party.
She said she tried to help Olesen out of the bathroom but he went into business class.
She said that he pushed her with his hand on her shoulder. Just leave. He had hit me.
She asked Ian for help, and her colleagues helped her out.
She said that she could hear Mr. Olsen shouting while she was carrying out her service.
The passenger pressed the call bell to inform the attendant that Mr Olesen had urinated on the male, his seat and the aisle.
Olesen swore at the cabin service director several times.
The captain of the flight told police that he had held discussions with his colleagues about the possibility of taking the flight back if the situation got out of hand.
He said he entered the cabin and saw a trail of liquid going from first class to the back of the plane after he was informed that Olesen had urinated in the aisle.
Olesen was described as a hard-working individual who was dedicated to his profession by Poulter.
He said he took some sleeping pills, but had not given any sleeping tablets to Thorbjorn, and that he helped Olesen back to his seat.
"He looked a little worse for wear and I assumed he had had too much to drink," said Poulter.
The court heard that Rose kept coming into the galley to see what was going on.
A member of the cabin crew noticed a small group of people gathered around seat 2E and they had brightly coloured pills.
She said she heard someone say "oh I'll have one of those" but she didn't know who it was.
Olesen said in a police interview that he had taken some pills on the plane.
He said he had had five or six drinks before the flight but denied he was drunk.
The trial continues.
