GATCHINA, Russia (AP) — In a sense, Alexei Gromov and his wife Tatyana began their lives together in the sky, when he proposed to her on a small, private plane he'd hired to make a romantic gesture.

Less than two years later, their lives ended together on another plane, a Russian jetliner that plunged into the Sinai Peninsula in Egypt on Saturday, killing all 224 aboard. Their toddler daughter was the youngest victim.

As Russians reel with the shock of their country's worst air disaster — all but four of those killed were Russian — the deaths of 27-year-old Alexei, 24-year-old Tatyana and 10-month-old Darina have particular resonance.

Before they left for their holiday in Egypt, Tatyana Gromov posted a photo on social media of Darina in St. Petersburg's Pulkovo airport, staring at planes with infant wonder, her small hands pressed against a window.

"The main passenger," her mother wrote.

Air travel was embedded in Alexei Gromov's life. His father was a military pilot and he wanted to be one himself before going to work as an IT specialist.

Their hometown of Gatchina, 40 kilometers (25 miles) south of St. Petersburg, was an early center of Russia's aircraft industry. A monument topped with a MiG-21 fighter jet commemorates the country's first military airfield.

Under that plane, near Alexei Gromov's parents' apartment, friends of the young couple laid flowers and toys and lit candles in their memory Wednesday.

"He was such a good friend — sympathetic, kind, sincere, reliable," said Alexei Savchenko, who had known Alexei Gromov since ninth grade.

"I saw him for the last time on the eve of their trip to Egypt. He was in such a good mood, all ready to have a vacation, to swim in the warm sea and to sunbathe," he said.

Andrei Dorokhin, 27, another friend, said Alexei Gromov was "always ready to lend his shoulder to someone."

"When my wife and I just began our family life, I worked a lot and she was pregnant. It was a hard time for us, and it was Alexei who helped us a lot at that time," he remembered.

Dorokhin said Gromov was a determined sort, organizing a school football team and managing to induce even the lazy to come to practices.

By Russian standards, Alexei waited late to get married, a matter of some teasing from his friends. But when he and Tatyana wed in the summer of 2014, it looked like waiting was the right strategy.

"They were like one united body," said another friend, Andrei Iliyn. "Tatyana was his first love, serious and real love. They were really happy together."