RxJava2 Maybe return empty Observable if no element - kotlin

Question

Is there a better / more idiomatic way to use a Maybe type from JavaRx 2 than flatMap and try/catch? The following example takes a Maybe<User> and tries to book them a random ticket for a flight. If the user doesn't exist, return an empty Observable.
fun bookRandomTicketFor(userId: UUID): Observable<Ticket> {
val agencies = travelAgents() // Observable<TravelAgency>
val user = findById(userId) // Maybe<User>
val location = locate() // Observable<GeoLocation>
return Observable
.just(user.toObservable())
.flatMap { usr ->
try {
usr.zipWith(location, { aUser, location ->
agencies
.flatMap { agency ->
agency
.search(aUser, location) // Observable<Flight>.
.toList() // Convert to List<Flight>.
.toObservable() // And to Observable<List<Flight>>.
.flatMap { flights -> // So it can be shuffled,
Observable.just( // giving a random order.
shuffle(flights as MutableList<Flight>)[0]
)
}
}.firstElement() // Now take the first randomly shuffled Flight.
}).flatMap { flight ->
book(user.toObservable(), flight.toObservable())
}
} catch (ex: Exception) {
Observable.empty<Ticket>()
}
}
.doOnSubscribe { Logger.log("Random ticket: start for $userId") }
.doOnComplete { Logger.log("Random ticket: exit for $userId") }
}
It seems a bit of a fudge to have to convert the Maybe<User> to an Observable and start with an Observable<Observable<User>> that I can then flatMap and try/catch. Just wondering if there is a neater approach to doing this?