The aircraft was seen by thousands over Tividale on Monday afternoon carrying the message 'Key, will you marry me?' .
The special proposal had been arranged by Nathan Cannon for Keeley Farndon without her knowing on the day of their anniversary.
Keeley said: "I was like 'oh my God' – I was so so shocked and I'm still in a bit of a state of shock now. It's not every day you're waiting to go out for a walk and you get called into the garden to see your name in the sky.
"I didn't know what to say – other than it was a 'yes' – but I wasn't expecting it at all. We first got together aged 18 so it's been a long time and we've done everything else first – it's something we hadn't talked about.
"We knew it was going to be on the cards at some point, but I'm a nurse and my now-fiancée is an assembly technician so we've used that time to get our careers started.
"And our time is taken up with our two-year-old – that's why I was even more shocked. It was so lovely and amazing."
The 27-year-old, who works as a neo-natal nurse at City Hospital in Birmingham, said she had no idea Nathan, also aged 27, was planning something – "not for a single second".
Miss Fardon, who called the ring "a beauty", added: "He had been speaking to the pilot for over a year to organise it and my fiancée isn't the type of person to be in the lime-light and stuff, he is very private as is our relationship, so I didn't expect it and I'm glad everyone loved it as well.
"It was the perfect way [to propose], really. Our dog was there and our daughter was there and she was copying me – she was jumping up and down.
"They [my family] are really really pleased, but what made it even more special is that we've waited – and we've got our daughter to celebrate our wedding with us."
The couple went out for a meal at a Miller and Carter steak restaurant after the proposal to celebrate.