* About 120,000 greet pope at Czech airfield
* Visit aimed to draw Czechs back to Church
* Pope urges faithful to look to God in struggle for freedom
By Michael Kahn
BRNO, Czech Republic, Sept 27 (Reuters) - Some 120,000 worshippers turned out at an airfield on Sunday for mass led by Pope Benedict as part of his visit aimed at drawing Czechs and other secular Europeans back to the Church.
Waving national flags from several neighbouring countries, the crowd heard the pope urge people gathered in the country's second-biggest city to keep God in their lives.
Many in the crowd came from nearby Poland, Slovakia and Hungary to greet the pope in the Czech Republic, where centuries of religious wars and decades of brutal Communist repression have made it one of the world's most secular countries.
"History has demonstrated the absurdities to which man descends when he excludes God from the horizon of his choices and actions, and how hard it is to build a society inspired by the values of goodness, justice and fraternity, because the human being is free and his freedom remains fragile," the pope said.
The three-day visit is his first trip to the central European country in 12 years and precedes the 20th anniversary in November of the 'Velvet Revolution' that ended decades of Communist totalitarian rule.
The Church has struggled with faltering appeal in a nation where about a third of the country's 10.5 million residents identify themselves as Catholic.
"Your country, like other nations, is experiencing cultural conditions that often present a radical challenge to faith and therefore also to hope," the pope said.
Unlike in neighbouring Poland, most leaders of the Czechoslovak state that emerged from the collapse of the Austro-Hungarian empire in 1918 were avowedly secular, or more in tune with the reformist tradition of the medieval priest Jan Hus -- a heretic for the Catholic Church.
Four decades of Communist rule starting in 1948 suppressed religious activity, and the government closed monasteries and jailed many priests and believers.
"Even though not many of us in the Czech Republic are Catholic so it is important to show our faith," said Matous, a 27-year-old from Olomouc among the crowd greeting the pope. "We want to celebrate mass with the head of our Church."
But many local residents took advantage of sunny weather to head to their cottages.
Radek Jasek of Brno said he considered it like any other big festival or concert that takes place in town.
"The people seem to enjoy it so as long as I know in advance that the highway will be closed I can avoid the crowds," he said.
Benedict was due to celebrate another mass on Monday in Stara Boleslav, north of Prague, where the Czech patron saint, Wenceslas, was murdered in the 10th century. The St. Wenceslas Day on Monday is a national holiday in the country. (Writing by Jan Lopatka; Editing by Charles Dick)